about summary refs log tree commit diff
path: root/io/tst-copy_file_range.c
blob: d8f4e8ac0402ec88bbdc22ba17df86699693d594 (plain) (blame)
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
/* Tests for copy_file_range.
   Copyright (C) 2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <array_length.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>
#include <poll.h>
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <support/test-driver.h>
#include <support/xunistd.h>
#include <sys/mount.h>

/* Boolean flags which indicate whether to use pointers with explicit
   output flags.  */
static int do_inoff;
static int do_outoff;

/* Name and descriptors of the input files.  Files are truncated and
   reopened (with O_RDWR) between tests.  */
static char *infile;
static int infd;
static char *outfile;
static int outfd;

/* Like the above, but on a different file system.  xdevfile can be
   NULL if no suitable file system has been found.  */
static char *xdevfile;

/* Input and output offsets.  Set according to do_inoff and do_outoff
   before the test.  The offsets themselves are always set to
   zero.  */
static off64_t inoff;
static off64_t *pinoff;
static off64_t outoff;
static off64_t *poutoff;

/* These are a collection of copy sizes used in tests.  The selection
   takes into account that the fallback implementation uses an
   internal buffer of 8192 bytes.  */
enum { maximum_size = 99999 };
static const int typical_sizes[] =
  { 0, 1, 2, 3, 1024, 2048, 4096, 8191, 8192, 8193, 16383, 16384, 16385,
    maximum_size };

/* The random contents of this array can be used as a pattern to check
   for correct write operations.  */
static unsigned char random_data[maximum_size];

/* The size chosen by the test harness.  */
static int current_size;

/* Maximum writable file offset.  Updated by find_maximum_offset
   below.  */
static off64_t maximum_offset;

/* Error code when crossing the offset.  */
static int maximum_offset_errno;

/* If true: Writes which cross the limit will fail.  If false: Writes
   which cross the limit will result in a partial write.  */
static bool maximum_offset_hard_limit;

/* Fills maximum_offset etc. above.  Truncates outfd as a side
   effect.  */
static void
find_maximum_offset (void)
{
  xftruncate (outfd, 0);
  if (maximum_offset != 0)
    return;

  uint64_t upper = -1;
  upper >>= 1;                  /* Maximum of off64_t.  */
  TEST_VERIFY ((off64_t) upper > 0);
  TEST_VERIFY ((off64_t) (upper + 1) < 0);
  if (lseek64 (outfd, upper, SEEK_SET) >= 0)
    {
      if (write (outfd, "", 1) == 1)
        FAIL_EXIT1 ("created a file larger than the off64_t range");
    }

  uint64_t lower = 1024 * 1024; /* A reasonable minimum file size.  */
  /* Loop invariant: writing at lower succeeds, writing at upper fails.  */
  while (lower + 1 < upper)
    {
      uint64_t middle = (lower + upper) / 2;
      if (test_verbose > 0)
        printf ("info: %s: remaining test range %" PRIu64 " .. %" PRIu64
                ", probe at %" PRIu64 "\n", __func__, lower, upper, middle);
      xftruncate (outfd, 0);
      if (lseek64 (outfd, middle, SEEK_SET) >= 0
          && write (outfd, "", 1) == 1)
        lower = middle;
      else
        upper = middle;
    }
  TEST_VERIFY (lower + 1 == upper);
  maximum_offset = lower;
  printf ("info: maximum writable file offset: %" PRIu64 " (%" PRIx64 ")\n",
          lower, lower);

  /* Check that writing at the valid offset actually works.  */
  xftruncate (outfd, 0);
  xlseek (outfd, lower, SEEK_SET);
  TEST_COMPARE (write (outfd, "", 1), 1);

  /* Cross the boundary with a two-byte write.  This can either result
     in a short write, or a failure.  */
  xlseek (outfd, lower, SEEK_SET);
  ssize_t ret = write (outfd, " ", 2);
  if (ret < 0)
    {
      maximum_offset_errno = errno;
      maximum_offset_hard_limit = true;
    }
  else
    maximum_offset_hard_limit = false;

  /* Check that writing at the next offset actually fails.  This also
     obtains the expected errno value.  */
  xftruncate (outfd, 0);
  const char *action;
  if (lseek64 (outfd, lower + 1, SEEK_SET) != 0)
    {
      if (write (outfd, "", 1) != -1)
        FAIL_EXIT1 ("write to impossible offset %" PRIu64 " succeeded",
                    lower + 1);
      action = "writing";
      int errno_copy = errno;
      if (maximum_offset_hard_limit)
        TEST_COMPARE (errno_copy, maximum_offset_errno);
      else
        maximum_offset_errno = errno_copy;
    }
  else
    {
      action = "seeking";
      maximum_offset_errno = errno;
    }
  printf ("info: %s out of range fails with %m (%d)\n",
          action, maximum_offset_errno);

  xftruncate (outfd, 0);
  xlseek (outfd, 0, SEEK_SET);
}

/* Perform a copy of a file.  */
static void
simple_file_copy (void)
{
  xwrite (infd, random_data, current_size);

  int length;
  int in_skipped; /* Expected skipped bytes in input.  */
  if (do_inoff)
    {
      xlseek (infd, 1, SEEK_SET);
      inoff = 2;
      length = current_size - 3;
      in_skipped = 2;
    }
  else
    {
      xlseek (infd, 3, SEEK_SET);
      length = current_size - 5;
      in_skipped = 3;
    }
  int out_skipped; /* Expected skipped bytes before the written data.  */
  if (do_outoff)
    {
      xlseek (outfd, 4, SEEK_SET);
      outoff = 5;
      out_skipped = 5;
    }
  else
    {
      xlseek (outfd, 6, SEEK_SET);
      length = current_size - 6;
      out_skipped = 6;
    }
  if (length < 0)
    length = 0;

  TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                 length, 0), length);
  if (do_inoff)
    {
      TEST_COMPARE (inoff, 2 + length);
      TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 1);
    }
  else
    TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 3 + length);
  if (do_outoff)
    {
      TEST_COMPARE (outoff, 5 + length);
      TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 4);
    }
  else
    TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 6 + length);

  struct stat64 st;
  xfstat (outfd, &st);
  if (length > 0)
    TEST_COMPARE (st.st_size, out_skipped + length);
  else
    {
      /* If we did not write anything, we also did not add any
         padding.  */
      TEST_COMPARE (st.st_size, 0);
      return;
    }

  xlseek (outfd, 0, SEEK_SET);
  char *bytes = xmalloc (st.st_size);
  TEST_COMPARE (read (outfd, bytes, st.st_size), st.st_size);
  for (int i = 0; i < out_skipped; ++i)
    TEST_COMPARE (bytes[i], 0);
  TEST_VERIFY (memcmp (bytes + out_skipped, random_data + in_skipped,
                       length) == 0);
  free (bytes);
}

/* Test that reading from a pipe willfails.  */
static void
pipe_as_source (void)
{
  int pipefds[2];
  xpipe (pipefds);

  for (int length = 0; length < 2; ++length)
    {
      if (test_verbose > 0)
        printf ("info: %s: length=%d\n", __func__, length);

      /* Make sure that there is something to copy in the pipe.  */
      xwrite (pipefds[1], "@", 1);

      TEST_COMPARE (copy_file_range (pipefds[0], pinoff, outfd, poutoff,
                                     length, 0), -1);
      /* Linux 4.10 and later return EINVAL.  Older kernels return
         EXDEV.  */
      TEST_VERIFY (errno == EINVAL || errno == EXDEV);
      TEST_COMPARE (inoff, 0);
      TEST_COMPARE (outoff, 0);
      TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 0);

      /* Make sure that nothing was read.  */
      char buf = 'A';
      TEST_COMPARE (read (pipefds[0], &buf, 1), 1);
      TEST_COMPARE (buf, '@');
    }

  xclose (pipefds[0]);
  xclose (pipefds[1]);
}

/* Test that writing to a pipe fails.  */
static void
pipe_as_destination (void)
{
  /* Make sure that there is something to read in the input file.  */
  xwrite (infd, "abc", 3);
  xlseek (infd, 0, SEEK_SET);

  int pipefds[2];
  xpipe (pipefds);

  for (int length = 0; length < 2; ++length)
    {
      if (test_verbose > 0)
        printf ("info: %s: length=%d\n", __func__, length);

      TEST_COMPARE (copy_file_range (infd, pinoff, pipefds[1], poutoff,
                                     length, 0), -1);
      /* Linux 4.10 and later return EINVAL.  Older kernels return
         EXDEV.  */
      TEST_VERIFY (errno == EINVAL || errno == EXDEV);
      TEST_COMPARE (inoff, 0);
      TEST_COMPARE (outoff, 0);
      TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);

      /* Make sure that nothing was written.  */
      struct pollfd pollfd = { .fd = pipefds[0], .events = POLLIN, };
      TEST_COMPARE (poll (&pollfd, 1, 0), 0);
    }

  xclose (pipefds[0]);
  xclose (pipefds[1]);
}

/* Test a write failure after (potentially) writing some bytes.
   Failure occurs near the start of the buffer.  */
static void
delayed_write_failure_beginning (void)
{
  /* We need to write something to provoke the error.  */
  if (current_size == 0)
    return;
  xwrite (infd, random_data, sizeof (random_data));
  xlseek (infd, 0, SEEK_SET);

  /* Write failure near the start.  The actual error code varies among
     file systems.  */
  find_maximum_offset ();
  off64_t where = maximum_offset;

  if (current_size == 1)
    ++where;
  outoff = where;
  if (do_outoff)
    xlseek (outfd, 1, SEEK_SET);
  else
    xlseek (outfd, where, SEEK_SET);
  if (maximum_offset_hard_limit || where > maximum_offset)
    {
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     sizeof (random_data), 0), -1);
      TEST_COMPARE (errno, maximum_offset_errno);
      TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
      TEST_COMPARE (inoff, 0);
      if (do_outoff)
        TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 1);
      else
        TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), where);
      TEST_COMPARE (outoff, where);
      struct stat64 st;
      xfstat (outfd, &st);
      TEST_COMPARE (st.st_size, 0);
    }
  else
    {
      /* The offset is not a hard limit.  This means we write one
         byte.  */
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     sizeof (random_data), 0), 1);
      if (do_inoff)
        {
          TEST_COMPARE (inoff, 1);
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
        }
      else
        {
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 1);
          TEST_COMPARE (inoff, 0);
        }
      if (do_outoff)
        {
          TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 1);
          TEST_COMPARE (outoff, where + 1);
        }
      else
        {
          TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), where + 1);
          TEST_COMPARE (outoff, where);
        }
      struct stat64 st;
      xfstat (outfd, &st);
      TEST_COMPARE (st.st_size, where + 1);
    }
}

/* Test a write failure after (potentially) writing some bytes.
   Failure occurs near the end of the buffer.  */
static void
delayed_write_failure_end (void)
{
  if (current_size <= 1)
    /* This would be same as the first test because there is not
       enough data to write to make a difference.  */
    return;
  xwrite (infd, random_data, sizeof (random_data));
  xlseek (infd, 0, SEEK_SET);

  find_maximum_offset ();
  off64_t where = maximum_offset - current_size + 1;
  if (current_size == sizeof (random_data))
    /* Otherwise we do not reach the non-writable byte.  */
    ++where;
  outoff = where;
  if (do_outoff)
    xlseek (outfd, 1, SEEK_SET);
  else
    xlseek (outfd, where, SEEK_SET);
  ssize_t ret = copy_file_range (infd, pinoff, outfd, poutoff,
                                 sizeof (random_data), 0);
  if (ret < 0)
    {
      TEST_COMPARE (ret, -1);
      TEST_COMPARE (errno, maximum_offset_errno);
      struct stat64 st;
      xfstat (outfd, &st);
      TEST_COMPARE (st.st_size, 0);
    }
  else
    {
      /* The first copy succeeded.  This happens in the emulation
         because the internal buffer of limited size does not
         necessarily cross the off64_t boundary on the first write
         operation.  */
      if (test_verbose > 0)
        printf ("info:   copy_file_range (%zu) returned %zd\n",
                sizeof (random_data), ret);
      TEST_VERIFY (ret > 0);
      TEST_VERIFY (ret < maximum_size);
      struct stat64 st;
      xfstat (outfd, &st);
      TEST_COMPARE (st.st_size, where + ret);
      if (do_inoff)
        {
          TEST_COMPARE (inoff, ret);
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
        }
      else
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), ret);

      char *buffer = xmalloc (ret);
      TEST_COMPARE (pread64 (outfd, buffer, ret, where), ret);
      TEST_VERIFY (memcmp (buffer, random_data, ret) == 0);
      free (buffer);

      /* The second copy fails.  */
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     sizeof (random_data), 0), -1);
      TEST_COMPARE (errno, maximum_offset_errno);
    }
}

/* Test a write failure across devices.  */
static void
cross_device_failure (void)
{
  if (xdevfile == NULL)
    /* Subtest not supported due to missing cross-device file.  */
    return;

  /* We need something to write.  */
  xwrite (infd, random_data, sizeof (random_data));
  xlseek (infd, 0, SEEK_SET);

  int xdevfd = xopen (xdevfile, O_RDWR | O_LARGEFILE, 0);
  TEST_COMPARE (copy_file_range (infd, pinoff, xdevfd, poutoff,
                                 current_size, 0), -1);
  TEST_COMPARE (errno, EXDEV);
  TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
  struct stat64 st;
  xfstat (xdevfd, &st);
  TEST_COMPARE (st.st_size, 0);

  xclose (xdevfd);
}

/* Try to exercise ENOSPC behavior with a tempfs file system (so that
   we do not have to fill up a regular file system to get the error).
   This function runs in a subprocess, so that we do not change the
   mount namespace of the actual test process.  */
static void
enospc_failure_1 (void *closure)
{
#ifdef CLONE_NEWNS
  support_become_root ();

  /* Make sure that we do not alter the file system mounts of the
     parents.  */
  if (! support_enter_mount_namespace ())
    {
      printf ("warning: ENOSPC test skipped\n");
      return;
    }

  char *mountpoint = closure;
  if (mount ("none", mountpoint, "tmpfs", MS_NODEV | MS_NOEXEC,
             "size=500k") != 0)
    {
      printf ("warning: could not mount tmpfs at %s: %m\n", mountpoint);
      return;
    }

  /* The source file must reside on the same file system.  */
  char *intmpfsfile = xasprintf ("%s/%s", mountpoint, "in");
  int intmpfsfd = xopen (intmpfsfile, O_RDWR | O_CREAT | O_LARGEFILE, 0600);
  xwrite (intmpfsfd, random_data, sizeof (random_data));
  xlseek (intmpfsfd, 1, SEEK_SET);
  inoff = 1;

  char *outtmpfsfile = xasprintf ("%s/%s", mountpoint, "out");
  int outtmpfsfd = xopen (outtmpfsfile, O_RDWR | O_CREAT | O_LARGEFILE, 0600);

  /* Fill the file with data until ENOSPC is reached.  */
  while (true)
    {
      ssize_t ret = write (outtmpfsfd, random_data, sizeof (random_data));
      if (ret < 0 && errno != ENOSPC)
        FAIL_EXIT1 ("write to %s: %m", outtmpfsfile);
      if (ret < sizeof (random_data))
        break;
    }
  TEST_COMPARE (write (outtmpfsfd, "", 1), -1);
  TEST_COMPARE (errno, ENOSPC);
  off64_t maxsize = xlseek (outtmpfsfd, 0, SEEK_CUR);
  TEST_VERIFY_EXIT (maxsize > sizeof (random_data));

  /* Constructed the expected file contents.  */
  char *expected = xmalloc (maxsize);
  TEST_COMPARE (pread64 (outtmpfsfd, expected, maxsize, 0), maxsize);
  /* Go back a little, so some bytes can be written.  */
  enum { offset = 20000 };
  TEST_VERIFY_EXIT (offset < maxsize);
  TEST_VERIFY_EXIT (offset < sizeof (random_data));
  memcpy (expected + maxsize - offset, random_data + 1, offset);

  if (do_outoff)
    {
      outoff = maxsize - offset;
      xlseek (outtmpfsfd, 2, SEEK_SET);
    }
  else
    xlseek (outtmpfsfd, -offset, SEEK_CUR);

  /* First call is expected to succeed because we made room for some
     bytes.  */
  TEST_COMPARE (copy_file_range (intmpfsfd, pinoff, outtmpfsfd, poutoff,
                                 maximum_size, 0), offset);
  if (do_inoff)
    {
      TEST_COMPARE (inoff, 1 + offset);
      TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1);
    }
  else
      TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1 + offset);
  if (do_outoff)
    {
      TEST_COMPARE (outoff, maxsize);
      TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), 2);
    }
  else
    TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), maxsize);
  struct stat64 st;
  xfstat (outtmpfsfd, &st);
  TEST_COMPARE (st.st_size, maxsize);
  char *actual = xmalloc (st.st_size);
  TEST_COMPARE (pread64 (outtmpfsfd, actual, st.st_size, 0), st.st_size);
  TEST_VERIFY (memcmp (expected, actual, maxsize) == 0);

  /* Second call should fail with ENOSPC.  */
  TEST_COMPARE (copy_file_range (intmpfsfd, pinoff, outtmpfsfd, poutoff,
                                 maximum_size, 0), -1);
  TEST_COMPARE (errno, ENOSPC);

  /* Offsets should be unchanged.  */
  if (do_inoff)
    {
      TEST_COMPARE (inoff, 1 + offset);
      TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1);
    }
  else
    TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1 + offset);
  if (do_outoff)
    {
      TEST_COMPARE (outoff, maxsize);
      TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), 2);
    }
  else
    TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), maxsize);
  TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_END), maxsize);
  TEST_COMPARE (pread64 (outtmpfsfd, actual, maxsize, 0), maxsize);
  TEST_VERIFY (memcmp (expected, actual, maxsize) == 0);

  free (actual);
  free (expected);

  xclose (intmpfsfd);
  xclose (outtmpfsfd);
  free (intmpfsfile);
  free (outtmpfsfile);

#else /* !CLONE_NEWNS */
  puts ("warning: ENOSPC test skipped (no mount namespaces)");
#endif
}

/* Call enospc_failure_1 in a subprocess.  */
static void
enospc_failure (void)
{
  char *mountpoint
    = support_create_temp_directory ("tst-copy_file_range-enospc-");
  support_isolate_in_subprocess (enospc_failure_1, mountpoint);
  free (mountpoint);
}

/* The target file descriptor must have O_APPEND enabled.  */
static void
oappend_failure (void)
{
  /* Add data, to make sure we do not fail because there is
     insufficient input data.  */
  xwrite (infd, random_data, current_size);
  xlseek (infd, 0, SEEK_SET);

  xclose (outfd);
  outfd = xopen (outfile, O_RDWR | O_APPEND, 0);
  TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                 current_size, 0), -1);
  TEST_COMPARE (errno, EBADF);
}

/* Test that a short input file results in a shortened copy.  */
static void
short_copy (void)
{
  if (current_size == 0)
    /* Nothing to shorten.  */
    return;

  /* Two subtests, one with offset 0 and current_size - 1 bytes, and
     another one with current_size bytes, but offset 1.  */
  for (int shift = 0; shift < 2; ++shift)
    {
      if (test_verbose > 0)
        printf ("info:   shift=%d\n", shift);
      xftruncate (infd, 0);
      xlseek (infd, 0, SEEK_SET);
      xwrite (infd, random_data, current_size - !shift);

      if (do_inoff)
        {
          inoff = shift;
          xlseek (infd, 2, SEEK_SET);
        }
      else
        {
          inoff = 3;
          xlseek (infd, shift, SEEK_SET);
        }
      ftruncate (outfd, 0);
      xlseek (outfd, 0, SEEK_SET);
      outoff = 0;

      /* First call copies current_size - 1 bytes.  */
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     current_size, 0), current_size - 1);
      char *buffer = xmalloc (current_size);
      TEST_COMPARE (pread64 (outfd, buffer, current_size, 0),
                    current_size - 1);
      TEST_VERIFY (memcmp (buffer, random_data + shift, current_size - 1)
                   == 0);
      free (buffer);

      if (do_inoff)
        {
          TEST_COMPARE (inoff, current_size - 1 + shift);
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 2);
        }
      else
        TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), current_size - 1 + shift);
      if (do_outoff)
        {
          TEST_COMPARE (outoff, current_size - 1);
          TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 0);
        }
      else
        TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), current_size - 1);

      /* First call copies zero bytes.  */
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     current_size, 0), 0);
      /* And the offsets are unchanged.  */
      if (do_inoff)
        {
          TEST_COMPARE (inoff, current_size - 1 + shift);
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 2);
        }
      else
        TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), current_size - 1 + shift);
      if (do_outoff)
        {
          TEST_COMPARE (outoff, current_size - 1);
          TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 0);
        }
      else
        TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), current_size - 1);
    }
}

/* A named test function.  */
struct test_case
{
  const char *name;
  void (*func) (void);
  bool sizes; /* If true, call the test with different current_size values.  */
};

/* The available test cases.  */
static struct test_case tests[] =
  {
    { "simple_file_copy", simple_file_copy, .sizes = true },
    { "pipe_as_source", pipe_as_source, },
    { "pipe_as_destination", pipe_as_destination, },
    { "delayed_write_failure_beginning", delayed_write_failure_beginning,
      .sizes = true },
    { "delayed_write_failure_end", delayed_write_failure_end, .sizes = true },
    { "cross_device_failure", cross_device_failure, .sizes = true },
    { "enospc_failure", enospc_failure, },
    { "oappend_failure", oappend_failure, .sizes = true },
    { "short_copy", short_copy, .sizes = true },
  };

static int
do_test (void)
{
  for (unsigned char *p = random_data; p < array_end (random_data); ++p)
    *p = rand () >> 24;

  infd = create_temp_file ("tst-copy_file_range-in-", &infile);
  xclose (create_temp_file ("tst-copy_file_range-out-", &outfile));

  /* Try to find a different directory from the default input/output
     file.  */
  {
    struct stat64 instat;
    xfstat (infd, &instat);
    static const char *const candidates[] =
      { NULL, "/var/tmp", "/dev/shm" };
    for (const char *const *c = candidates; c < array_end (candidates); ++c)
      {
        const char *path = *c;
        char *to_free = NULL;
        if (path == NULL)
          {
            to_free = xreadlink ("/proc/self/exe");
            path = dirname (to_free);
          }

        struct stat64 cstat;
        xstat (path, &cstat);
        if (cstat.st_dev == instat.st_dev)
          {
            free (to_free);
            continue;
          }

        printf ("info: using alternate temporary files directory: %s\n", path);
        xdevfile = xasprintf ("%s/tst-copy_file_range-xdev-XXXXXX", path);
        free (to_free);
        break;
      }
    if (xdevfile != NULL)
      {
        int xdevfd = mkstemp (xdevfile);
        if (xdevfd < 0)
          FAIL_EXIT1 ("mkstemp (\"%s\"): %m", xdevfile);
        struct stat64 xdevst;
        xfstat (xdevfd, &xdevst);
        TEST_VERIFY (xdevst.st_dev != instat.st_dev);
        add_temp_file (xdevfile);
        xclose (xdevfd);
      }
    else
      puts ("warning: no alternate directory on different file system found");
  }
  xclose (infd);

  for (do_inoff = 0; do_inoff < 2; ++do_inoff)
    for (do_outoff = 0; do_outoff < 2; ++do_outoff)
      for (struct test_case *test = tests; test < array_end (tests); ++test)
        for (const int *size = typical_sizes;
             size < array_end (typical_sizes); ++size)
          {
            current_size = *size;
            if (test_verbose > 0)
              printf ("info: %s do_inoff=%d do_outoff=%d current_size=%d\n",
                      test->name, do_inoff, do_outoff, current_size);

            inoff = 0;
            if (do_inoff)
              pinoff = &inoff;
            else
              pinoff = NULL;
            outoff = 0;
            if (do_outoff)
              poutoff = &outoff;
            else
              poutoff = NULL;

            infd = xopen (infile, O_RDWR | O_LARGEFILE, 0);
            xftruncate (infd, 0);
            outfd = xopen (outfile, O_RDWR | O_LARGEFILE, 0);
            xftruncate (outfd, 0);

            test->func ();

            xclose (infd);
            xclose (outfd);

            if (!test->sizes)
              /* Skip the other sizes unless they have been
                 requested.  */
              break;
          }

  free (infile);
  free (outfile);
  free (xdevfile);

  return 0;
}

#include <support/test-driver.c>