summaryrefslogtreecommitdiff
path: root/src/remove.c
blob: a75694c6b1459f82f0b7ba1170b97622ff6c37b1 (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
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
/* remove.c -- core functions for removing files and directories
   Copyright (C) 88, 90, 91, 1994-2002 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.  */

/* Extracted from rm.c and librarified by Jim Meyering.  */

#ifdef _AIX
 #pragma alloca
#endif

#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <assert.h>

#include "save-cwd.h"
#include "system.h"
#include "dirname.h"
#include "error.h"
#include "file-type.h"
#include "hash.h"
#include "hash-pjw.h"
#include "obstack.h"
#include "quote.h"
#include "remove.h"

/* Avoid shadowing warnings because these are functions declared
   in dirname.h as well as locals used below.  */
#define dir_name rm_dir_name
#define dir_len rm_dir_len

#define obstack_chunk_alloc malloc
#define obstack_chunk_free free

#ifndef PARAMS
# if defined (__GNUC__) || __STDC__
#  define PARAMS(args) args
# else
#  define PARAMS(args) ()
# endif
#endif

/* FIXME: if possible, use autoconf...  */
#ifdef __GLIBC__
# define ROOT_CAN_UNLINK_DIRS 0
#else
# define ROOT_CAN_UNLINK_DIRS 1
#endif

enum Ternary
  {
    T_UNKNOWN = 2,
    T_NO,
    T_YES
  };
typedef enum Ternary Ternary;

/* The prompt function may be called twice a given directory.
   The first time, we ask whether to descend into it, and the
   second time, we ask whether to remove it.  */
enum Prompt_action
  {
    PA_DESCEND_INTO_DIR = 2,
    PA_REMOVE_DIR
  };

/* On systems with an lstat function that accepts the empty string,
   arrange to make lstat calls go through the wrapper function.  */
#if HAVE_LSTAT_EMPTY_STRING_BUG
int rpl_lstat PARAMS((const char *, struct stat *));
# define lstat(Name, Stat_buf) rpl_lstat(Name, Stat_buf)
#endif

#ifdef D_INO_IN_DIRENT
# define D_INO(dp) ((dp)->d_ino)
# define ENABLE_CYCLE_CHECK
#else
/* Some systems don't have inodes, so fake them to avoid lots of ifdefs.  */
# define D_INO(dp) 1
#endif

#if !defined S_ISLNK
# define S_ISLNK(Mode) 0
#endif

/* Initial capacity of per-directory hash table of entries that have
   been processed but not been deleted.  */
#define HT_UNREMOVABLE_INITIAL_CAPACITY 13

/* An entry in the active directory stack.
   Each entry corresponds to an `active' directory.  */
struct AD_ent
{
  /* For a given active directory, this is the set of names of
     entries in that directory that could/should not be removed.
     For example, `.' and `..', as well as files/dirs for which
     unlink/rmdir failed e.g., due to access restrictions.  */
  Hash_table *unremovable;

  /* Record the status for a given active directory; we need to know
     whether an entry was not removed, either because of an error or
     because the user declined.  */
  enum RM_status status;

  union
  {
    /* The directory's dev/ino.  Used to ensure that `chdir some-subdir', then
       `chdir ..' takes us back to the same directory from which we started).
       (valid for all but the bottommost entry on the stack.  */
    struct dev_ino a;

    /* Enough information to restore the initial working directory.
       (valid only for the bottommost entry on the stack)  */
    struct saved_cwd saved_cwd;
  } u;
};

int euidaccess ();
int yesno ();

extern char *program_name;

/* The name of the directory (starting with and relative to a command
   line argument) being processed.  When a subdirectory is entered, a new
   component is appended (pushed).  When RM chdir's out of a directory,
   the top component is removed (popped).  This is used to form a full
   file name when necessary.  */
static struct obstack dir_stack;

/* Stack of lengths of directory names (including trailing slash)
   appended to dir_stack.  We have to have a separate stack of lengths
   (rather than just popping back to previous slash) because the first
   element pushed onto the dir stack may contain slashes.  */
static struct obstack len_stack;

/* Stack of active directory entries.
   The first `active' directory is the initial working directory.
   Additional active dirs are pushed onto the stack as rm `chdir's
   into each nonempty directory it must remove.  When rm has finished
   removing the hierarchy under a directory, it pops the active dir stack.  */
static struct obstack Active_dir;

static void
hash_freer (void *x)
{
  free (x);
}

static bool
hash_compare_strings (void const *x, void const *y)
{
  return STREQ (x, y) ? true : false;
}

static inline void
push_dir (const char *dir_name)
{
  size_t len;

  len = strlen (dir_name);

  /* Append the string onto the stack.  */
  obstack_grow (&dir_stack, dir_name, len);

  /* Append a trailing slash.  */
  obstack_1grow (&dir_stack, '/');

  /* Add one for the slash.  */
  ++len;

  /* Push the length (including slash) onto its stack.  */
  obstack_grow (&len_stack, &len, sizeof (len));
}

/* Return the entry name of the directory on the top of the stack
   in malloc'd storage.  */
static inline char *
top_dir (void)
{
  int n_lengths = obstack_object_size (&len_stack) / sizeof (size_t);
  size_t *length = (size_t *) obstack_base (&len_stack);
  size_t top_len = length[n_lengths - 1];
  char const *p = obstack_next_free (&dir_stack) - top_len;
  char *q = xmalloc (top_len);
  memcpy (q, p, top_len - 1);
  q[top_len - 1] = 0;
  return q;
}

static inline void
pop_dir (void)
{
  int n_lengths = obstack_object_size (&len_stack) / sizeof (size_t);
  size_t *length = (size_t *) obstack_base (&len_stack);
  size_t top_len;

  assert (n_lengths > 0);
  top_len = length[n_lengths - 1];
  assert (top_len >= 2);

  /* Pop off the specified length of pathname.  */
  assert (obstack_object_size (&dir_stack) >= top_len);
  obstack_blank (&dir_stack, -top_len);

  /* Pop the length stack, too.  */
  assert (obstack_object_size (&len_stack) >= sizeof (size_t));
  obstack_blank (&len_stack, (int) -(sizeof (size_t)));
}

/* Copy the SRC_LEN bytes of data beginning at SRC into the DST_LEN-byte
   buffer, DST, so that the last source byte is at the end of the destination
   buffer.  If SRC_LEN is longer than DST_LEN, then set *TRUNCATED to non-zero.
   Set *RESULT to point to the beginning of (the portion of) the source data
   in DST.  Return the number of bytes remaining in the destination buffer.  */

static size_t
right_justify (char *dst, size_t dst_len, const char *src, size_t src_len,
	       char **result, int *truncated)
{
  const char *sp;
  char *dp;

  if (src_len <= dst_len)
    {
      sp = src;
      dp = dst + (dst_len - src_len);
      *truncated = 0;
    }
  else
    {
      sp = src + (src_len - dst_len);
      dp = dst;
      src_len = dst_len;
      *truncated = 1;
    }

  *result = memcpy (dp, sp, src_len);
  return dst_len - src_len;
}

/* Using the global directory name obstack, create the full path to FILENAME.
   Return it in sometimes-realloc'd space that should not be freed by the
   caller.  Realloc as necessary.  If realloc fails, use a static buffer
   and put as long a suffix in that buffer as possible.  */

static char *
full_filename (const char *filename)
{
  static char *buf = NULL;
  static size_t n_allocated = 0;

  int dir_len = obstack_object_size (&dir_stack);
  char *dir_name = (char *) obstack_base (&dir_stack);
  size_t n_bytes_needed;
  size_t filename_len;

  filename_len = strlen (filename);
  n_bytes_needed = dir_len + filename_len + 1;

  if (n_bytes_needed > n_allocated)
    {
      /* This code requires that realloc accept NULL as the first arg.
         This function must not use xrealloc.  Otherwise, an out-of-memory
	 error involving a file name to be expanded here wouldn't ever
	 be issued.  Use realloc and fall back on using a static buffer
	 if memory allocation fails.  */
      buf = realloc (buf, n_bytes_needed);
      n_allocated = n_bytes_needed;

      if (buf == NULL)
	{
#define SBUF_SIZE 512
#define ELLIPSES_PREFIX "[...]"
	  static char static_buf[SBUF_SIZE];
	  int truncated;
	  size_t len;
	  char *p;

	  len = right_justify (static_buf, SBUF_SIZE, filename,
			       filename_len + 1, &p, &truncated);
	  right_justify (static_buf, len, dir_name, dir_len, &p, &truncated);
	  if (truncated)
	    {
	      memcpy (static_buf, ELLIPSES_PREFIX,
		      sizeof (ELLIPSES_PREFIX) - 1);
	    }
	  return p;
	}
    }

  /* Copy directory part, including trailing slash, and then
     append the filename part, including a trailing zero byte.  */
  memcpy (mempcpy (buf, dir_name, dir_len), filename, filename_len + 1);

  assert (strlen (buf) + 1 == n_bytes_needed);

  return buf;
}

static size_t
AD_stack_height (void)
{
  return obstack_object_size (&Active_dir) / sizeof (struct AD_ent);
}

static struct AD_ent *
AD_stack_top (void)
{
  return (struct AD_ent *)
    ((char *) obstack_next_free (&Active_dir) - sizeof (struct AD_ent));
}

static void
AD_stack_pop (void)
{
  /* operate on Active_dir.  pop and free top entry */
  struct AD_ent *top = AD_stack_top ();
  if (top->unremovable)
    hash_free (top->unremovable);
  obstack_blank (&Active_dir, -sizeof (struct AD_ent));
  pop_dir ();
}

/* chdir `up' one level.
   Whenever using chdir '..', verify that the post-chdir
   dev/ino numbers for `.' match the saved ones.
   Return the name (in malloc'd storage) of the
   directory (usually now empty) from which we're coming.  */
static char *
AD_pop_and_chdir (void)
{
  /* Get the name of the current directory from the top of the stack.  */
  char *dir = top_dir ();
  enum RM_status old_status = AD_stack_top()->status;
  struct stat sb;
  struct AD_ent *top;

  AD_stack_pop ();

  /* Propagate any failure to parent.  */
  UPDATE_STATUS (AD_stack_top()->status, old_status);

  assert (AD_stack_height ());

  top = AD_stack_top ();
  if (1 < AD_stack_height ())
    {
      /* We can give a better diagnostic here, since the target is relative. */
      if (chdir (".."))
	{
	  error (EXIT_FAILURE, errno,
		 _("cannot chdir from %s to .."),
		 quote (full_filename (".")));
	}
    }
  else
    {
      if (restore_cwd (&top->u.saved_cwd, NULL, NULL))
	exit (EXIT_FAILURE);
    }

  if (lstat (".", &sb))
    error (EXIT_FAILURE, errno,
	   _("cannot lstat `.' in %s"), quote (full_filename (".")));

  if (1 < AD_stack_height ())
    {
      /*  Ensure that post-chdir dev/ino match the stored ones.  */
      if ( ! SAME_INODE (sb, top->u.a))
	error (EXIT_FAILURE, 0,
	       _("%s changed dev/ino"), quote (full_filename (".")));
    }

  return dir;
}

/* Initialize *HT if it is NULL.
   Insert FILENAME into HT.  */
static void
AD_mark_helper (Hash_table **ht, char const *filename)
{
  if (*ht == NULL)
    *ht = hash_initialize (HT_UNREMOVABLE_INITIAL_CAPACITY, NULL, hash_pjw,
			   hash_compare_strings, hash_freer);
  if (*ht == NULL)
    xalloc_die ();
  if (! hash_insert (*ht, filename))
    xalloc_die ();
}

/* Mark FILENAME (in current directory) as unremovable.  */
static void
AD_mark_as_unremovable (char const *filename)
{
  AD_mark_helper (&AD_stack_top()->unremovable, xstrdup (filename));
}

/* Mark the current directory as unremovable.  I.e., mark the entry
   in the parent directory corresponding to `.'.
   This happens e.g., when an opendir fails and the only name
   the caller has conveniently at hand is `.'.  */
static void
AD_mark_current_as_unremovable (void)
{
  struct AD_ent *top = AD_stack_top ();
  const char *curr = top_dir ();

  assert (1 < AD_stack_height ());

  --top;
  AD_mark_helper (&top->unremovable, curr);
}

/* Push the initial cwd info onto the stack.
   This will always be the bottommost entry on the stack.  */
static void
AD_push_initial (struct saved_cwd const *cwd)
{
  struct AD_ent *top;

  /* Extend the stack.  */
  obstack_blank (&Active_dir, sizeof (struct AD_ent));

  /* Fill in the new values.  */
  top = AD_stack_top ();
  top->u.saved_cwd = *cwd;
  top->status = RM_OK;
  top->unremovable = NULL;
}

/* Push info about the current working directory (".") onto the
   active directory stack.  DIR is the ./-relative name through
   which we've just `chdir'd to this directory.  DIR_SB_FROM_PARENT
   is the result of calling lstat on DIR from the parent of DIR.  */
static void
AD_push (char const *dir, struct stat const *dir_sb_from_parent)
{
  struct stat sb;
  struct AD_ent *top;

  push_dir (dir);

  if (lstat (".", &sb))
    error (EXIT_FAILURE, errno,
	   _("cannot lstat `.' in %s"), quote (full_filename (".")));

  if ( ! SAME_INODE (sb, *dir_sb_from_parent))
    error (EXIT_FAILURE, errno,
	   _("%s changed dev/ino"), quote (full_filename (".")));

  /* Extend the stack.  */
  obstack_blank (&Active_dir, sizeof (struct AD_ent));

  /* Fill in the new values.  */
  top = AD_stack_top ();
  top->u.a.st_dev = sb.st_dev;
  top->u.a.st_ino = sb.st_ino;
  top->status = RM_OK;
  top->unremovable = NULL;
}

static int
AD_is_removable (char const *file)
{
  struct AD_ent *top = AD_stack_top ();
  return ! (top->unremovable && hash_lookup (top->unremovable, file));
}

static inline bool
is_power_of_two (unsigned int i)
{
  return (i & (i - 1)) == 0;
}

static void
cycle_check (struct stat const *sb)
{
#ifdef ENABLE_CYCLE_CHECK
  /* If there is a directory cycle, detect it (lazily) and die.  */
  static struct dev_ino dir_cycle_detect_dev_ino;
  static unsigned int chdir_counter;

  /* If the current directory ever happens to be the same
     as the one we last recorded for the cycle detection,
     then it's obviously part of a cycle.  */
  if (chdir_counter && SAME_INODE (*sb, dir_cycle_detect_dev_ino))
    {
      error (0, 0, _("\
WARNING: Circular directory structure.\n\
This almost certainly means that you have a corrupted file system.\n\
NOTIFY YOUR SYSTEM MANAGER.\n\
The following directory is part of the cycle:\n  %s\n"),
	     quote (full_filename (".")));
      exit (EXIT_FAILURE);
    }

  /* If the number of `descending' chdir calls is a power of two,
     record the dev/ino of the current directory.  */
  if (is_power_of_two (++chdir_counter))
    {
      dir_cycle_detect_dev_ino.st_dev = sb->st_dev;
      dir_cycle_detect_dev_ino.st_ino = sb->st_ino;
    }
#endif
}

static bool
is_empty_dir (char const *dir)
{
  DIR *dirp = opendir (dir);
  if (dirp == NULL)
    {
      closedir (dirp);
      return false;
    }

  while (1)
    {
      struct dirent *dp;
      const char *f;

      errno = 0;
      dp = readdir (dirp);
      if (dp == NULL)
	{
	  closedir (dirp);
	  return errno == 0 ? true : false;
	}

      f = dp->d_name;
      if ( ! DOT_OR_DOTDOT (f))
	{
	  closedir (dirp);
	  return false;
	}
    }
}

/* Prompt whether to remove FILENAME, if required via a combination of
   the options specified by X and/or file attributes.  If the file may
   be removed, return RM_OK.  If the user declines to remove the file,
   return RM_USER_DECLINED.  If not ignoring missing files and we
   cannot lstat FILENAME, then return RM_ERROR.

   Depending on MODE, ask whether to `descend into' or to `remove' the
   directory FILENAME.  MODE is ignored when FILENAME is not a directory.
   Set *IS_EMPTY to T_YES if FILENAME is an empty directory, and it is
   appropriate to try to remove it with rmdir (e.g. recursive mode).
   Don't even try to set *IS_EMPTY when MODE == PA_REMOVE_DIR.
   Set *IS_DIR to T_YES or T_NO if we happen to determine whether
   FILENAME is a directory.  */
static enum RM_status
prompt (char const *filename, struct rm_options const *x,
	enum Prompt_action mode, Ternary *is_dir, Ternary *is_empty)
{
  int write_protected = 0;
  *is_empty = T_UNKNOWN;
  *is_dir = T_UNKNOWN;

  if ((!x->ignore_missing_files && (x->interactive || x->stdin_tty)
       && (write_protected = (euidaccess (filename, W_OK) && errno == EACCES)))
      || x->interactive)
    {
      struct stat sbuf;
      if (lstat (filename, &sbuf))
	{
	  /* lstat failed.  This happens e.g., with `rm '''.  */
	  error (0, errno, _("cannot lstat %s"),
		 quote (full_filename (filename)));
	  return RM_ERROR;
	}

      /* Using permissions doesn't make sense for symlinks.  */
      if (S_ISLNK (sbuf.st_mode))
	{
	  if ( ! x->interactive)
	    return RM_OK;
	  write_protected = 0;
	}

      /* Issue the prompt.  */
      {
	char const *quoted_name = quote (full_filename (filename));

	*is_dir = (S_ISDIR (sbuf.st_mode) ? T_YES : T_NO);

	/* FIXME: use a variant of error (instead of fprintf) that doesn't
	   append a newline.  Then we won't have to declare program_name in
	   this file.  */
	if (S_ISDIR (sbuf.st_mode)
	    && x->recursive
	    && mode == PA_DESCEND_INTO_DIR
	    && ((*is_empty = (is_empty_dir (filename) ? T_YES : T_NO))
		== T_NO))
	  fprintf (stderr,
		   (write_protected
		    ? _("%s: descend into write-protected directory %s? ")
		    : _("%s: descend into directory %s? ")),
		   program_name, quoted_name);
	else
	  {
	    /* TRANSLATORS: You may find it more convenient to translate
	       the equivalent of _("%1$s: %3$s is write-protected and is
	       of type `%2$s'.  Remove it? ").  This is more verbose than
	       the original but it should avoid grammatical problems with
	       the output of file_type.  */
	    fprintf (stderr,
		     (write_protected
		      ? _("%s: remove write-protected %s %s? ")
		      : _("%s: remove %s %s? ")),
		     program_name, file_type (&sbuf), quoted_name);
	  }

	if (!yesno ())
	  return RM_USER_DECLINED;
      }
    }
  return RM_OK;
}

#if HAVE_STRUCT_DIRENT_D_TYPE
# define DT_IS_DIR(D) ((D)->d_type == DT_DIR)
#else
/* Use this only if the member exists -- i.e., don't return 0.  */
# define DT_IS_DIR(D) do_not_use_this_macro
#endif

#define DO_UNLINK(Filename, X)						\
  do									\
    {									\
      if (unlink (Filename) == 0)					\
	{								\
	  if ((X)->verbose)						\
	    printf (_("removed %s\n"), quote (full_filename (Filename))); \
	  return RM_OK;							\
	}								\
									\
      if (errno == ENOENT && (X)->ignore_missing_files)			\
	return RM_OK;							\
    }									\
  while (0)

#define DO_RMDIR(Filename, X)				\
  do							\
    {							\
      if (rmdir (Filename) == 0)			\
	{						\
	  if ((X)->verbose)				\
	    printf (_("removed directory: %s\n"),	\
		    quote (full_filename (Filename)));	\
	  return RM_OK;					\
	}						\
							\
      if (errno == ENOENT && (X)->ignore_missing_files)	\
	return RM_OK;					\
							\
      if (errno == ENOTEMPTY || errno == EEXIST)	\
	return RM_NONEMPTY_DIR;				\
    }							\
  while (0)

/* Remove the file or directory specified by FILENAME.
   Return RM_OK if it is removed, and RM_ERROR or RM_USER_DECLINED if not.
   But if FILENAME specifies a non-empty directory, return RM_NONEMPTY_DIR. */

static enum RM_status
remove_entry (char const *filename, struct rm_options const *x,
	      struct dirent const *dp)
{
  Ternary is_dir;
  Ternary is_empty_directory;
  enum RM_status s = prompt (filename, x, PA_DESCEND_INTO_DIR,
			     &is_dir, &is_empty_directory);

  if (s != RM_OK)
    return s;

  /* Why bother with the following #if/#else block?  Because on systems with
     an unlink function that *can* unlink directories, we must determine the
     type of each entry before removing it.  Otherwise, we'd risk unlinking an
     entire directory tree simply by unlinking a single directory;  then all
     the storage associated with that hierarchy would not be freed until the
     next reboot.  Not nice.  To avoid that, on such slightly losing systems, we
     need to call lstat to determine the type of each entry, and that represents
     extra overhead that -- it turns out -- we can avoid on GNU-libc-based
     systems, since there, unlink will never remove a directory.  */

#if ROOT_CAN_UNLINK_DIRS

  /* If we don't already know whether FILENAME is a directory, find out now.
     Then, if it's a non-directory, we can use unlink on it.  */
  if (is_dir == T_UNKNOWN)
    {
# if HAVE_STRUCT_DIRENT_D_TYPE
      if (dp)
	is_dir = DT_IS_DIR (dp) ? T_YES : T_NO;
      else
# endif
	{
	  struct stat sbuf;
	  if (lstat (filename, &sbuf))
	    {
	      if (errno == ENOENT && x->ignore_missing_files)
		return RM_OK;

	      error (0, errno,
		     _("cannot lstat %s"), quote (full_filename (filename)));
	      return RM_ERROR;
	    }

	  is_dir = S_ISDIR (sbuf.st_mode) ? T_YES : T_NO;
	}
    }

  if (is_dir == T_NO)
    {
      /* At this point, barring race conditions, FILENAME is known
	 to be a non-directory, so it's ok to try to unlink it.  */
      DO_UNLINK (filename, x);

      /* unlink failed with some other error code.  report it.  */
      error (0, errno, _("cannot remove %s"),
	     quote (full_filename (filename)));
      return RM_ERROR;
    }

  if (! x->recursive)
    {
      error (0, EISDIR, _("cannot remove directory %s"),
	     quote (full_filename (filename)));
      return RM_ERROR;
    }

  if (is_empty_directory == T_YES)
    {
      DO_RMDIR (filename, x);
      /* Don't diagnose any failure here.
	 It'll be detected when the caller tries another way.  */
    }


#else

  /* is_empty_directory is set iff it's ok to use rmdir.
     Note that it's set only in interactive mode -- in which case it's
     an optimization that arranges so that the user is asked just
     once whether to remove the directory.  */
  if (is_empty_directory == T_YES)
    DO_RMDIR (filename, x);

  /* If we happen to know that FILENAME is a directory, return now
     and let the caller remove it -- this saves the overhead of a failed
     unlink call.  If FILENAME is a command-line argument, then dp is NULL,
     so we'll first try to unlink it.  Using unlink here is ok, because it
     cannot remove a directory.  */
  if ((dp && DT_IS_DIR (dp)) || is_dir == T_YES)
    return RM_NONEMPTY_DIR;

  DO_UNLINK (filename, x);

  /* Accept either EISDIR or EPERM as an indication that FILENAME may be
     a directory.  POSIX says that unlink must set errno to EPERM when it
     fails to remove a directory, while Linux-2.4.18 sets it to EISDIR.  */
  if ((errno != EISDIR && errno != EPERM) || ! x->recursive)
    {
      /* some other error code.  Report it and fail.
	 Likewise, if we're trying to remove a directory without
	 the --recursive option.  */
      error (0, errno, _("cannot remove %s"),
	     quote (full_filename (filename)));
      return RM_ERROR;
    }
#endif

  return RM_NONEMPTY_DIR;
}

/* Remove entries in `.', the current working directory (cwd).
   Upon finding a directory that is both non-empty and that can be chdir'd
   into, return zero and set *SUBDIR and fill in SUBDIR_SB, where
   SUBDIR is the malloc'd name of the subdirectory if the chdir succeeded,
   NULL otherwise (e.g., if opendir failed or if there was no subdirectory).
   Likewise, SUBDIR_SB is the result of calling lstat on SUBDIR.
   Return RM_OK if all entries are removed.  Remove RM_ERROR if any
   entry cannot be removed.  Otherwise, return RM_USER_DECLINED if
   the user declines to remove at least one entry.  Remove as much as
   possible, continuing even if we fail to remove some entries.  */
static enum RM_status
remove_cwd_entries (char **subdir, struct stat *subdir_sb,
		    struct rm_options const *x)
{
  DIR *dirp = opendir (".");
  struct AD_ent *top = AD_stack_top ();
  enum RM_status status = top->status;

  assert (VALID_STATUS (status));
  *subdir = NULL;

  if (dirp == NULL)
    {
      if (errno != ENOENT || !x->ignore_missing_files)
	{
	  error (0, errno, _("cannot open directory %s"),
		 quote (full_filename (".")));
	  return RM_ERROR;
	}
    }

  while (1)
    {
      struct dirent *dp;
      enum RM_status tmp_status;
      const char *f;

      /* Set errno to zero so we can distinguish between a readdir failure
	 and when readdir simply finds that there are no more entries.  */
      errno = 0;
      if ((dp = readdir (dirp)) == NULL)
	{
	  if (errno)
	    {
	      /* Save/restore errno across closedir call.  */
	      int e = errno;
	      closedir (dirp);
	      errno = e;

	      /* Arrange to give a diagnostic after exiting this loop.  */
	      dirp = NULL;
	    }
	  break;
	}

      f = dp->d_name;
      if (DOT_OR_DOTDOT (f))
	continue;

      /* Skip files we've already tried/failed to remove.  */
      if ( ! AD_is_removable (f))
	continue;

      /* Pass dp->d_type info to remove_entry so the non-glibc
	 case can decide whether to use unlink or chdir.
	 Systems without the d_type member will have to endure
	 the performance hit of first calling lstat F. */
      tmp_status = remove_entry (f, x, dp);
      switch (tmp_status)
	{
	case RM_OK:
	  /* do nothing */
	  break;

	case RM_ERROR:
	case RM_USER_DECLINED:
	  AD_mark_as_unremovable (f);
	  UPDATE_STATUS (status, tmp_status);
	  break;

	case RM_NONEMPTY_DIR:
	  /* Record dev/ino of F so that we can compare
	     that with dev/ino of `.' after the chdir.
	     This dev/ino pair is also used in cycle detection.  */
	  if (lstat (f, subdir_sb))
	    error (EXIT_FAILURE, errno, _("cannot lstat %s"),
		   quote (full_filename (f)));

	  if (chdir (f))
	    {
	      error (0, errno, _("cannot chdir from %s to %s"),
		     quote_n (0, full_filename (".")), quote_n (1, f));
	      AD_mark_as_unremovable (f);
	      status = RM_ERROR;
	      break;
	    }
	  cycle_check (subdir_sb);

	  *subdir = xstrdup (f);
	  break;
	}

      /* Record status for this directory.  */
      UPDATE_STATUS (top->status, status);

      if (*subdir)
	break;
    }

  if (dirp == NULL || CLOSEDIR (dirp) != 0)
    {
      /* Note that this diagnostic serves for both readdir
	 and closedir failures.  */
      error (0, errno, _("reading directory %s"), quote (full_filename (".")));
      status = RM_ERROR;
    }

  return status;
}

/*  Remove the hierarchy rooted at DIR.
    Do that by changing into DIR, then removing its contents, then
    returning to the original working directory and removing DIR itself.
    Don't use recursion.  Be careful when using chdir ".." that we
    return to the same directory from which we came, if necessary.
    Return 1 for success, 0 if some file cannot be removed or if
    a chdir fails.
    If the working directory cannot be restored, exit immediately.  */

static enum RM_status
remove_dir (char const *dir, struct saved_cwd **cwd_state,
	    struct rm_options const *x)
{
  enum RM_status status;
  struct stat dir_sb;

  /* Save any errno (from caller's failed remove_entry call), in case DIR
     is not a directory, so that we can give a reasonable diagnostic.  */
  int saved_errno = errno;

  if (*cwd_state == NULL)
    {
      *cwd_state = XMALLOC (struct saved_cwd, 1);
      if (save_cwd (*cwd_state))
	return RM_ERROR;
      AD_push_initial (*cwd_state);
    }

  /* There is a race condition in that an attacker could replace the nonempty
     directory, DIR, with a symlink between the preceding call to rmdir
     (in our caller) and the chdir below.  However, the following lstat,
     along with the `stat (".",...' and dev/ino comparison in AD_push
     ensure that we detect it and fail.  */

  if (lstat (dir, &dir_sb))
    {
      error (0, errno,
	     _("cannot lstat %s"), quote (full_filename (dir)));
      return RM_ERROR;
    }

  if (chdir (dir))
    {
      if (! S_ISDIR (dir_sb.st_mode))
	{
	  /* This happens on Linux-2.4.18 when a non-privileged user tries
	     to delete a file that is owned by another user in a directory
	     like /tmp that has the S_ISVTX flag set.  */
	  assert (saved_errno == EPERM);
	  error (0, saved_errno,
		 _("cannot remove %s"), quote (full_filename (dir)));
	}
      else
	{
	  error (0, errno,
		 _("cannot chdir from %s to %s"),
		 quote_n (0, full_filename (".")), quote_n (1, dir));
	}
      return RM_ERROR;
    }

  AD_push (dir, &dir_sb);

  status = RM_OK;

  while (1)
    {
      char *subdir = NULL;
      struct stat subdir_sb;
      enum RM_status tmp_status = remove_cwd_entries (&subdir, &subdir_sb, x);
      if (tmp_status != RM_OK)
	{
	  UPDATE_STATUS (status, tmp_status);
	  AD_mark_current_as_unremovable ();
	}
      if (subdir)
	{
	  AD_push (subdir, &subdir_sb);
	  free (subdir);
	  continue;
	}

      /* Execution reaches this point when we've removed the last
	 removable entry from the current directory.  */
      {
	char *d = AD_pop_and_chdir ();

	/* Try to remove D only if remove_cwd_entries succeeded.  */
	if (tmp_status == RM_OK)
	  {
	    /* This does a little more work than necessary when it actually
	       prompts the user.  E.g., we already know that D is a directory
	       and that it's almost certainly empty, yet we lstat it.
	       But that's no big deal since we're interactive.  */
	    Ternary is_dir;
	    Ternary is_empty;
	    enum RM_status s = prompt (d, x, PA_REMOVE_DIR, &is_dir, &is_empty);

	    if (s != RM_OK)
	      {
		free (d);
		return s;
	      }

	    if (rmdir (d) == 0)
	      {
		if (x->verbose)
		  printf (_("removed directory: %s\n"),
			  quote (full_filename (d)));
	      }
	    else
	      {
		error (0, errno, _("cannot remove directory %s"),
		       quote (full_filename (d)));
		AD_mark_as_unremovable (d);
		status = RM_ERROR;
		UPDATE_STATUS (AD_stack_top()->status, status);
	      }
	  }

	free (d);

	if (AD_stack_height () == 1)
	  break;
      }
    }

  return status;
}

/* Remove the file or directory specified by FILENAME.
   Return RM_OK if it is removed, and RM_ERROR or RM_USER_DECLINED if not.
   On input, the first time this function is called, CWD_STATE should be
   the address of a NULL pointer.  Do not modify it for any subsequent calls.
   On output, it is either that same NULL pointer or the address of
   a malloc'd `struct saved_cwd' that may be freed.  */

static enum RM_status
rm_1 (char const *filename,
      struct rm_options const *x, struct saved_cwd **cwd_state)
{
  char *base = base_name (filename);
  enum RM_status status;

  if (DOT_OR_DOTDOT (base))
    {
      error (0, 0, _("cannot remove `.' or `..'"));
      return RM_ERROR;
    }

  status = remove_entry (filename, x, NULL);
  if (status != RM_NONEMPTY_DIR)
    return status;

  return remove_dir (filename, cwd_state, x);
}

/* Remove all files and/or directories specified by N_FILES and FILE.
   Apply the options in X.  */
enum RM_status
rm (size_t n_files, char const *const *file, struct rm_options const *x)
{
  struct saved_cwd *cwd_state = NULL;
  enum RM_status status = RM_OK;
  size_t i;

  obstack_init (&dir_stack);
  obstack_init (&len_stack);
  obstack_init (&Active_dir);

  for (i = 0; i < n_files; i++)
    {
      enum RM_status s = rm_1 (file[i], x, &cwd_state);
      assert (VALID_STATUS (s));
      UPDATE_STATUS (status, s);
    }

  obstack_free (&dir_stack, NULL);
  obstack_free (&len_stack, NULL);
  obstack_free (&Active_dir, NULL);

  XFREE (cwd_state);

  return status;
}