summaryrefslogtreecommitdiffstats
path: root/contrib/tar/src/misc.c
blob: 8ece9c6ffd3ff8da724419249c2e49a22e32c031 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
/* Miscellaneous functions, not really specific to GNU tar.

   Copyright 1988, 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001 Free
   Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2, or (at your option) any later
   version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
   Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* $FreeBSD$ */

#include "system.h"
#include "rmt.h"
#include "common.h"
#include <quotearg.h>
#include <save-cwd.h>

static void call_arg_fatal PARAMS ((char const *, char const *))
     __attribute__ ((noreturn));

/* Handling strings.  */

/* Assign STRING to a copy of VALUE if not zero, or to zero.  If
   STRING was nonzero, it is freed first.  */
void
assign_string (char **string, const char *value)
{
  if (*string)
    free (*string);
  *string = value ? xstrdup (value) : 0;
}

/* Allocate a copy of the string quoted as in C, and returns that.  If
   the string does not have to be quoted, it returns a null pointer.
   The allocated copy should normally be freed with free() after the
   caller is done with it.

   This is used in one context only: generating the directory file in
   incremental dumps.  The quoted string is not intended for human
   consumption; it is intended only for unquote_string.  The quoting
   is locale-independent, so that users needn't worry about locale
   when reading directory files.  This means that we can't use
   quotearg, as quotearg is locale-dependent and is meant for human
   consumption.  */
char *
quote_copy_string (const char *string)
{
  const char *source = string;
  char *destination = 0;
  char *buffer = 0;
  int copying = 0;

  while (*source)
    {
      int character = *source++;

      switch (character)
	{
	case '\n': case '\\':
	  if (!copying)
	    {
	      size_t length = (source - string) - 1;

	      copying = 1;
	      buffer = xmalloc (length + 2 + 2 * strlen (source) + 1);
	      memcpy (buffer, string, length);
	      destination = buffer + length;
	    }
	  *destination++ = '\\';
	  *destination++ = character == '\\' ? '\\' : 'n';
	  break;

	default:
	  if (copying)
	    *destination++ = character;
	  break;
	}
    }
  if (copying)
    {
      *destination = '\0';
      return buffer;
    }
  return 0;
}

/* Takes a quoted C string (like those produced by quote_copy_string)
   and turns it back into the un-quoted original.  This is done in
   place.  Returns 0 only if the string was not properly quoted, but
   completes the unquoting anyway.
 									   
   This is used for reading the saved directory file in incremental
   dumps.  It is used for decoding old `N' records (demangling names).
   But also, it is used for decoding file arguments, would they come
   from the shell or a -T file, and for decoding the --exclude
   argument.  */
int
unquote_string (char *string)
{
  int result = 1;
  char *source = string;
  char *destination = string;

  /* Escape sequences other than \\ and \n are no longer generated by
     quote_copy_string, but accept them for backwards compatibility,
     and also because unquote_string is used for purposes other than
     parsing the output of quote_copy_string.  */

  while (*source)
    if (*source == '\\')
      switch (*++source)
	{
	case '\\':
	  *destination++ = '\\';
	  source++;
	  break;

	case 'n':
	  *destination++ = '\n';
	  source++;
	  break;

	case 't':
	  *destination++ = '\t';
	  source++;
	  break;

	case 'f':
	  *destination++ = '\f';
	  source++;
	  break;

	case 'b':
	  *destination++ = '\b';
	  source++;
	  break;

	case 'r':
	  *destination++ = '\r';
	  source++;
	  break;

	case '?':
	  *destination++ = 0177;
	  source++;
	  break;

	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	  {
	    int value = *source++ - '0';

	    if (*source < '0' || *source > '7')
	      {
		*destination++ = value;
		break;
	      }
	    value = value * 8 + *source++ - '0';
	    if (*source < '0' || *source > '7')
	      {
		*destination++ = value;
		break;
	      }
	    value = value * 8 + *source++ - '0';
	    *destination++ = value;
	    break;
	  }

	default:
	  result = 0;
	  *destination++ = '\\';
	  if (*source)
	    *destination++ = *source++;
	  break;
	}
    else if (source != destination)
      *destination++ = *source++;
    else
      source++, destination++;

  if (source != destination)
    *destination = '\0';
  return result;
}

/* Return nonzero if NAME contains ".." as a path name component.  */
int
contains_dot_dot (char const *name)
{
  char const *p = name + FILESYSTEM_PREFIX_LEN (name);

  for (;;)
    {
      if (p[0] == '.' && p[1] == '.' && (ISSLASH (p[2]) || !p[2]))
	return 1;

      do
	{
	  if (! *p++)
	    return 0;
	}
      while (! ISSLASH (*p));

      do
	{
	  if (! *p++)
	    return 0;
	}
      while ( ISSLASH (*p));
    }
}

/* File handling.  */

/* Saved names in case backup needs to be undone.  */
static char *before_backup_name;
static char *after_backup_name;

/* Some implementations of rmdir let you remove the working directory.
   Report an error with errno set to zero for obvious cases of this;
   otherwise call rmdir.  */
static int
safer_rmdir (const char *path)
{
  while (path[0] == '.' && ISSLASH (path[1]))
    {
      path++;

      do path++;
      while (ISSLASH (*path));
    }

  if (! path[0] || (path[0] == '.' && ! path[1]))
    {
      errno = 0;
      return -1;
    }

  return rmdir (path);
}

/* Remove PATH.  If PATH is a directory, then if RECURSE is set remove
   it recursively; otherwise, remove it only if it is empty.  Return 0
   on error, with errno set; if PATH is obviously the working
   directory return zero with errno set to zero.  */
int
remove_any_file (const char *path, int recurse)
{
  /* Try unlink first if we are not root, as this saves us a system
     call in the common case where we're removing a non-directory.  */
  if (! we_are_root)
    {
      if (unlink (path) == 0)
	return 1;
      if (errno != EPERM)
	return 0;
    }

  if (safer_rmdir (path) == 0)
    return 1;

  switch (errno)
    {
    case ENOTDIR:
      return we_are_root && unlink (path) == 0;

    case 0:
    case EEXIST:
#if defined ENOTEMPTY && ENOTEMPTY != EEXIST
    case ENOTEMPTY:
#endif
      if (recurse)
	{
	  char *directory = savedir (path);
	  char const *entry;
	  size_t entrylen;

	  if (! directory)
	    return 0;

	  for (entry = directory;
	       (entrylen = strlen (entry)) != 0;
	       entry += entrylen + 1)
	    {
	      char *path_buffer = new_name (path, entry);
	      int r = remove_any_file (path_buffer, 1);
	      int e = errno;
	      free (path_buffer);

	      if (! r)
		{
		  free (directory);
		  errno = e;
		  return 0;
		}
	    }

	  free (directory);
	  return safer_rmdir (path) == 0;
	}
      break;
    }

  return 0;
}

/* Check if PATH already exists and make a backup of it right now.
   Return success (nonzero) only if the backup in either unneeded, or
   successful.  For now, directories are considered to never need
   backup.  If ARCHIVE is nonzero, this is the archive and so, we do
   not have to backup block or character devices, nor remote entities.  */
int
maybe_backup_file (const char *path, int archive)
{
  struct stat file_stat;

  /* Check if we really need to backup the file.  */

  if (archive && _remdev (path))
    return 1;

  if (stat (path, &file_stat))
    {
      if (errno == ENOENT)
	return 1;

      stat_error (path);
      return 0;
    }

  if (S_ISDIR (file_stat.st_mode))
    return 1;

  if (archive && (S_ISBLK (file_stat.st_mode) || S_ISCHR (file_stat.st_mode)))
    return 1;

  assign_string (&before_backup_name, path);

  /* A run situation may exist between Emacs or other GNU programs trying to
     make a backup for the same file simultaneously.  If theoretically
     possible, real problems are unlikely.  Doing any better would require a
     convention, GNU-wide, for all programs doing backups.  */

  assign_string (&after_backup_name, 0);
  after_backup_name = find_backup_file_name (path, backup_type);
  if (! after_backup_name)
    xalloc_die ();

  if (rename (before_backup_name, after_backup_name) == 0)
    {
      if (verbose_option)
	fprintf (stdlis, _("Renaming %s to %s\n"),
		 quote_n (0, before_backup_name),
		 quote_n (1, after_backup_name));
      return 1;
    }
  else
    {
      /* The backup operation failed.  */
      int e = errno;
      ERROR ((0, e, _("%s: Cannot rename to %s"),
	      quotearg_colon (before_backup_name),
	      quote_n (1, after_backup_name)));
      assign_string (&after_backup_name, 0);
      return 0;
    }
}

/* Try to restore the recently backed up file to its original name.
   This is usually only needed after a failed extraction.  */
void
undo_last_backup (void)
{
  if (after_backup_name)
    {
      if (rename (after_backup_name, before_backup_name) != 0)
	{
	  int e = errno;
	  ERROR ((0, e, _("%s: Cannot rename to %s"),
		  quotearg_colon (after_backup_name),
		  quote_n (1, before_backup_name)));
	}
      if (verbose_option)
	fprintf (stdlis, _("Renaming %s back to %s\n"),
		 quote_n (0, after_backup_name),
		 quote_n (1, before_backup_name));
      assign_string (&after_backup_name, 0);
    }
}

/* Depending on DEREF, apply either stat or lstat to (NAME, BUF).  */
int
deref_stat (int deref, char const *name, struct stat *buf)
{
  return deref ? stat (name, buf) : lstat (name, buf);
}

/* A description of a working directory.  */
struct wd
{
  char const *name;
  int saved;
  struct saved_cwd saved_cwd;
};

/* A vector of chdir targets.  wd[0] is the initial working directory.  */
static struct wd *wd;

/* The number of working directories in the vector.  */
static size_t wds;

/* The allocated size of the vector.  */
static size_t wd_alloc;

/* DIR is the operand of a -C option; add it to vector of chdir targets,
   and return the index of its location.  */
int
chdir_arg (char const *dir)
{
  if (wds == wd_alloc)
    {
      wd_alloc = 2 * (wd_alloc + 1);
      wd = xrealloc (wd, sizeof *wd * wd_alloc);
      if (! wds)
	{
	  wd[wds].name = ".";
	  wd[wds].saved = 0;
	  wds++;
	}
    }

  /* Optimize the common special case of the working directory,
     or the working directory as a prefix.  */
  if (dir[0])
    {
      while (dir[0] == '.' && ISSLASH (dir[1]))
	for (dir += 2;  ISSLASH (*dir);  dir++)
	  continue;
      if (! dir[dir[0] == '.'])
	return wds - 1;
    }

  wd[wds].name = dir;
  wd[wds].saved = 0;
  return wds++;
}

/* Change to directory I.  If I is 0, change to the initial working
   directory; otherwise, I must be a value returned by chdir_arg.  */
void
chdir_do (int i)
{
  static int previous;

  if (previous != i)
    {
      struct wd *prev = &wd[previous];
      struct wd *curr = &wd[i];

      if (! prev->saved)
	{
	  prev->saved = 1;
	  if (save_cwd (&prev->saved_cwd) != 0)
	    FATAL_ERROR ((0, 0, _("Cannot save working directory")));
	}

      if (curr->saved)
	{
	  if (restore_cwd (&curr->saved_cwd, curr->name, prev->name))
	    FATAL_ERROR ((0, 0, _("Cannot change working directory")));
	}
      else
	{
	  if (i && ! ISSLASH (curr->name[0]))
	    chdir_do (i - 1);
	  if (chdir (curr->name) != 0)
	    chdir_fatal (curr->name);
	}

      previous = i;
    }
}

/* Decode MODE from its binary form in a stat structure, and encode it
   into a 9-byte string STRING, terminated with a NUL.  */

void
decode_mode (mode_t mode, char *string)
{
  *string++ = mode & S_IRUSR ? 'r' : '-';
  *string++ = mode & S_IWUSR ? 'w' : '-';
  *string++ = (mode & S_ISUID
	       ? (mode & S_IXUSR ? 's' : 'S')
	       : (mode & S_IXUSR ? 'x' : '-'));
  *string++ = mode & S_IRGRP ? 'r' : '-';
  *string++ = mode & S_IWGRP ? 'w' : '-';
  *string++ = (mode & S_ISGID
	       ? (mode & S_IXGRP ? 's' : 'S')
	       : (mode & S_IXGRP ? 'x' : '-'));
  *string++ = mode & S_IROTH ? 'r' : '-';
  *string++ = mode & S_IWOTH ? 'w' : '-';
  *string++ = (mode & S_ISVTX
	       ? (mode & S_IXOTH ? 't' : 'T')
	       : (mode & S_IXOTH ? 'x' : '-'));
  *string = '\0';
}

/* Report an error associated with the system call CALL and the
   optional name NAME.  */
static void
call_arg_error (char const *call, char const *name)
{
  int e = errno;
  ERROR ((0, e, _("%s: Cannot %s"), quotearg_colon (name), call));
}

/* Report a fatal error associated with the system call CALL and
   the optional file name NAME.  */
static void
call_arg_fatal (char const *call, char const *name)
{
  int e = errno;
  FATAL_ERROR ((0, e, _("%s: Cannot %s"), quotearg_colon (name),  call));
}

/* Report a warning associated with the system call CALL and
   the optional file name NAME.  */
static void
call_arg_warn (char const *call, char const *name)
{
  int e = errno;
  WARN ((0, e, _("%s: Warning: Cannot %s"), quotearg_colon (name), call));
}

void
chdir_fatal (char const *name)
{
  call_arg_fatal ("chdir", name);
}

void
chmod_error_details (char const *name, mode_t mode)
{
  int e = errno;
  ERROR ((0, e, _("%s: Cannot change mode to 0%o"),
	  quotearg_colon (name), mode));
}

void
chown_error_details (char const *name, uid_t uid, gid_t gid)
{
  int e = errno;
  ERROR ((0, e, _("%s: Cannot change ownership to uid %lu, gid %lu"),
	  quotearg_colon (name), (unsigned long) uid, (unsigned long) gid));
}

void
close_error (char const *name)
{
  call_arg_error ("close", name);
}

void
close_fatal (char const *name)
{
  call_arg_fatal ("close", name);
}

void
close_warn (char const *name)
{
  call_arg_warn ("close", name);
}

void
exec_fatal (char const *name)
{
  call_arg_fatal ("exec", name);
}

void
link_error (char const *target, char const *source)
{
  int e = errno;
  ERROR ((0, e, _("%s: Cannot hard link to %s"),
	  quotearg_colon (source), quote_n (1, target)));
}

void
mkdir_error (char const *name)
{
  call_arg_error ("mkdir", name);
}

void
mkfifo_error (char const *name)
{
  call_arg_error ("mkfifo", name);
}

void
mknod_error (char const *name)
{
  call_arg_error ("mknod", name);
}

void
open_error (char const *name)
{
  call_arg_error ("open", name);
}

void
open_fatal (char const *name)
{
  call_arg_fatal ("open", name);
}

void
open_warn (char const *name)
{
  call_arg_warn ("open", name);
}

void
read_error (char const *name)
{
  call_arg_error ("read", name);
}

void
read_error_details (char const *name, off_t offset, size_t size)
{
  char buf[UINTMAX_STRSIZE_BOUND];
  int e = errno;
  ERROR ((0, e,
	  _("%s: Read error at byte %s, reading %lu bytes"),
	  quotearg_colon (name), STRINGIFY_BIGINT (offset, buf),
	  (unsigned long) size));
}

void
read_warn_details (char const *name, off_t offset, size_t size)
{
  char buf[UINTMAX_STRSIZE_BOUND];
  int e = errno;
  WARN ((0, e,
	 _("%s: Warning: Read error at byte %s, reading %lu bytes"),
	 quotearg_colon (name), STRINGIFY_BIGINT (offset, buf),
	 (unsigned long) size));
}

void
read_fatal (char const *name)
{
  call_arg_fatal ("read", name);
}

void
read_fatal_details (char const *name, off_t offset, size_t size)
{
  char buf[UINTMAX_STRSIZE_BOUND];
  int e = errno;
  FATAL_ERROR ((0, e,
		_("%s: Read error at byte %s, reading %lu bytes"),
		quotearg_colon (name), STRINGIFY_BIGINT (offset, buf),
		(unsigned long) size));
}

void
readlink_error (char const *name)
{
  call_arg_error ("readlink", name);
}

void
readlink_warn (char const *name)
{
  call_arg_warn ("readlink", name);
}

void
savedir_error (char const *name)
{
  call_arg_error ("savedir", name);
}

void
savedir_warn (char const *name)
{
  call_arg_warn ("savedir", name);
}

void
seek_error (char const *name)
{
  call_arg_error ("seek", name);
}

void
seek_error_details (char const *name, off_t offset)
{
  char buf[UINTMAX_STRSIZE_BOUND];
  int e = errno;
  ERROR ((0, e, _("%s: Cannot seek to %s"),
	  quotearg_colon (name),
	  STRINGIFY_BIGINT (offset, buf)));
}

void
seek_warn (char const *name)
{
  call_arg_warn ("seek", name);
}

void
seek_warn_details (char const *name, off_t offset)
{
  char buf[UINTMAX_STRSIZE_BOUND];
  int e = errno;
  WARN ((0, e, _("%s: Warning: Cannot seek to %s"),
	 quotearg_colon (name),
	 STRINGIFY_BIGINT (offset, buf)));
}

void
symlink_error (char const *contents, char const *name)
{
  int e = errno;
  ERROR ((0, e, _("%s: Cannot create symlink to %s"),
	  quotearg_colon (name), quote_n (1, contents)));
}

void
stat_error (char const *name)
{
  call_arg_error ("stat", name);
}

void
stat_warn (char const *name)
{
  call_arg_warn ("stat", name);
}

void
truncate_error (char const *name)
{
  call_arg_error ("truncate", name);
}

void
truncate_warn (char const *name)
{
  call_arg_warn ("truncate", name);
}

void
unlink_error (char const *name)
{
  call_arg_error ("unlink", name);
}

void
utime_error (char const *name)
{
  call_arg_error ("utime", name);
}

void
waitpid_error (char const *name)
{
  call_arg_error ("waitpid", name);
}

void
write_error (char const *name)
{
  call_arg_error ("write", name);
}

void
write_error_details (char const *name, ssize_t status, size_t size)
{
  if (status < 0)
    write_error (name);
  else
    ERROR ((0, 0, _("%s: Wrote only %lu of %lu bytes"),
	    name, (unsigned long) status, (unsigned long) record_size));
}

void
write_fatal (char const *name)
{
  call_arg_fatal ("write", name);
}

void
write_fatal_details (char const *name, ssize_t status, size_t size)
{
  write_error_details (name, status, size);
  fatal_exit ();
}


/* Fork, aborting if unsuccessful.  */
pid_t
xfork (void)
{
  pid_t p = fork ();
  if (p == (pid_t) -1)
    call_arg_fatal ("fork", _("child process"));
  return p;
}

/* Create a pipe, aborting if unsuccessful.  */
void
xpipe (int fd[2])
{
  if (pipe (fd) < 0)
    call_arg_fatal ("pipe", _("interprocess channel"));
}

/* Return an unambiguous printable representation, allocated in slot N,
   for NAME, suitable for diagnostics.  */
char const *
quote_n (int n, char const *name)
{
  return quotearg_n_style (n, locale_quoting_style, name);
}

/* Return an unambiguous printable representation of NAME, suitable
   for diagnostics.  */
char const *
quote (char const *name)
{
  return quote_n (0, name);
}
OpenPOWER on IntegriCloud