aboutsummaryrefslogtreecommitdiff
path: root/tests/fs-tests/lib/tests.c
blob: 570672f706beee19416976d925e31c4f4e09570f (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
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
/*
 * Copyright (C) 2007 Nokia Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 * Author: Adrian Hunter
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/vfs.h>
#include <sys/statvfs.h>
#include <linux/jffs2.h>
#include <libgen.h>
#include <dirent.h>
#include <ctype.h>
#include <limits.h>
#include <sys/mount.h>
#include <mntent.h>
#include <time.h>

#include "tests.h"

char *tests_file_system_mount_dir = TESTS_DEFAULT_FILE_SYSTEM_MOUNT_DIR;

char *tests_file_system_type = TESTS_DEFAULT_FILE_SYSTEM_TYPE;

int tests_ok_to_sync = 0; /* Whether to use fsync */

/* General purpose test parameter to specify some aspect of test size.
   May be used by different tests in different ways or not at all.
   Set by the -z or --size option. */
int64_t tests_size_parameter = 0;

/* General purpose test parameter to specify some aspect of test repetition.
   May be used by different tests in different ways or not at all.
   Set by the -n, --repeat options. */
int64_t tests_repeat_parameter = 0;

/* General purpose test parameter to specify some aspect of test sleeping.
   May be used by different tests in different ways or not at all.
   Set by the -p, --sleep options. */
int64_t tests_sleep_parameter = 0;

/* Program name from argv[0] */
char *program_name = "unknown";

/* General purpose test parameter to specify a file should be unlinked.
   May be used by different tests in different ways or not at all. */
int tests_unlink_flag = 0;

/* General purpose test parameter to specify a file should be closed.
   May be used by different tests in different ways or not at all. */
int tests_close_flag = 0;

/* General purpose test parameter to specify a file should be deleted.
   May be used by different tests in different ways or not at all. */
int tests_delete_flag = 0;

/* General purpose test parameter to specify a file have a hole.
   May be used by different tests in different ways or not at all. */
int tests_hole_flag = 0;

/* Whether it is ok to test on the root file system */
static int rootok = 0;

/* Maximum file name length of test file system (from statfs) */
long tests_max_fname_len = 255;

/* Function invoked by the CHECK macro */
void tests_test(int test,const char *msg,const char *file,unsigned line)
{
	int eno;
	time_t t;

	if (test)
		return;
	eno = errno;
	time(&t);
	fprintf(stderr,	"Test failed: %s on %s"
			"Test failed: %s in %s at line %u\n",
			program_name, ctime(&t), msg, file, line);
	if (eno) {
		fprintf(stderr,"errno = %d\n",eno);
		fprintf(stderr,"strerror = %s\n",strerror(eno));
	}
	exit(1);
}

static int is_zero(const char *p)
{
	for (;*p;++p)
		if (*p != '0')
			return 0;
	return 1;
}

static void fold(const char *text, int width)
{
	int pos, bpos = 0;
	const char *p;
	char line[1024];

	if (width > 1023) {
		printf("%s\n", text);
		return;
	}
	p = text;
	pos = 0;
	while (p[pos]) {
		while (!isspace(p[pos])) {
			line[pos] = p[pos];
			if (!p[pos])
				break;
			++pos;
			if (pos == width) {
				line[pos] = '\0';
				printf("%s\n", line);
				p += pos;
				pos = 0;
			}
		}
		while (pos < width) {
			line[pos] = p[pos];
			if (!p[pos]) {
				bpos = pos;
				break;
			}
			if (isspace(p[pos]))
				bpos = pos;
			++pos;
		}
		line[bpos] = '\0';
		printf("%s\n", line);
		p += bpos;
		pos = 0;
		while (p[pos] && isspace(p[pos]))
			++p;
	}
}

/* Handle common program options */
int tests_get_args(int argc,
		char *argv[],
		const char *title,
		const char *desc,
		const char *opts)
{
	int run_test = 0;
	int display_help = 0;
	int display_title = 0;
	int display_description = 0;
	int i;
	char *s;

	program_name = argv[0];

	s = getenv("TEST_FILE_SYSTEM_MOUNT_DIR");
	if (s)
		tests_file_system_mount_dir = strdup(s);
	s = getenv("TEST_FILE_SYSTEM_TYPE");
	if (s)
		tests_file_system_type = strdup(s);

	run_test = 1;
	rootok = 1;
	for (i = 1; i < argc; ++i) {
		if (strcmp(argv[i], "--help") == 0 ||
				strcmp(argv[i], "-h") == 0)
			display_help = 1;
		else if (strcmp(argv[i], "--title") == 0 ||
				strcmp(argv[i], "-t") == 0)
			display_title = 1;
		else if (strcmp(argv[i], "--description") == 0 ||
				strcmp(argv[i], "-d") == 0)
			display_description = 1;
		else if (strcmp(argv[i], "--sync") == 0 ||
				strcmp(argv[i], "-s") == 0)
			tests_ok_to_sync = 1;
		else if (strncmp(argv[i], "--size", 6) == 0 ||
				strncmp(argv[i], "-z", 2) == 0) {
			int64_t n;
			char *p;
			if (i+1 < argc && !isdigit(argv[i][strlen(argv[i])-1]))
				++i;
			p = argv[i];
			while (*p && !isdigit(*p))
				++p;
			n = atoll(p);
			if (n)
				tests_size_parameter = n;
			else {
				int all_zero = 1;
				for (; all_zero && *p; ++p)
					if (*p != '0')
						all_zero = 0;
				if (all_zero)
					tests_size_parameter = 0;
				else
					display_help = 1;
			}
		} else if (strncmp(argv[i], "--repeat", 8) == 0 ||
				strncmp(argv[i], "-n", 2) == 0) {
			int64_t n;
			char *p;
			if (i+1 < argc && !isdigit(argv[i][strlen(argv[i])-1]))
				++i;
			p = argv[i];
			while (*p && !isdigit(*p))
				++p;
			n = atoll(p);
			if (n || is_zero(p))
				tests_repeat_parameter = n;
			else
				display_help = 1;
		} else if (strncmp(argv[i], "--sleep", 7) == 0 ||
				strncmp(argv[i], "-p", 2) == 0) {
			int64_t n;
			char *p;
			if (i+1 < argc && !isdigit(argv[i][strlen(argv[i])-1]))
				++i;
			p = argv[i];
			while (*p && !isdigit(*p))
				++p;
			n = atoll(p);
			if (n || is_zero(p))
				tests_sleep_parameter = n;
			else
				display_help = 1;
		} else if (strcmp(argv[i], "--unlink") == 0 ||
				strcmp(argv[i], "-u") == 0)
			tests_unlink_flag = 1;
		else if (strcmp(argv[i], "--hole") == 0 ||
				strcmp(argv[i], "-o") == 0)
			tests_hole_flag = 1;
		else if (strcmp(argv[i], "--close") == 0 ||
				strcmp(argv[i], "-c") == 0)
			tests_close_flag = 1;
		else if (strcmp(argv[i], "--delete") == 0 ||
				strcmp(argv[i], "-e") == 0)
			tests_delete_flag = 1;
		else
			display_help = 1;
	}

	if (display_help) {
		run_test = 0;
		display_title = 0;
		display_description = 0;
		if (!opts)
			opts = "";
		printf("File System Test Program\n\n");
		printf("Test Title: %s\n\n", title);
		printf("Usage is: %s [ options ]\n",argv[0]);
		printf("    Options are:\n");
		printf("        -h, --help            ");
		printf("Display this help\n");
		printf("        -t, --title           ");
		printf("Display the test title\n");
		printf("        -d, --description     ");
		printf("Display the test description\n");
		if (strchr(opts, 's')) {
			printf("        -s, --sync            ");
			printf("Make use of fsync\n");
		}
		if (strchr(opts, 'z')) {
			printf("        -z, --size            ");
			printf("Set size parameter\n");
		}
		if (strchr(opts, 'n')) {
			printf("        -n, --repeat          ");
			printf("Set repeat parameter\n");
		}
		if (strchr(opts, 'p')) {
			printf("        -p, --sleep           ");
			printf("Set sleep parameter\n");
		}
		if (strchr(opts, 'u')) {
			printf("        -u, --unlink          ");
			printf("Unlink file\n");
		}
		if (strchr(opts, 'o')) {
			printf("        -o, --hole            ");
			printf("Create a hole in a file\n");
		}
		if (strchr(opts, 'c')) {
			printf("        -c, --close           ");
			printf("Close file\n");
		}
		if (strchr(opts, 'e')) {
			printf("        -e, --delete          ");
			printf("Delete file\n");
		}
		printf("\nBy default, testing is done in directory ");
		printf("/mnt/test_file_system. To change this\nuse ");
		printf("environmental variable ");
		printf("TEST_FILE_SYSTEM_MOUNT_DIR. By default, ");
		printf("the file\nsystem tested is jffs2. To change this ");
		printf("set TEST_FILE_SYSTEM_TYPE.\n\n");
		printf("Test Description:\n");
		fold(desc, 80);
	} else {
		if (display_title)
			printf("%s\n", title);
		if (display_description)
			printf("%s\n", desc);
		if (display_title || display_description)
			if (argc == 2 || (argc == 3 &&
					display_title &&
					display_description))
				run_test = 0;
	}
	return run_test;
}

/* Return the number of files (or directories) in the given directory */
unsigned tests_count_files_in_dir(const char *dir_name)
{
	DIR *dir;
	struct dirent *entry;
	unsigned count = 0;

	dir = opendir(dir_name);
	CHECK(dir != NULL);
	for (;;) {
		errno = 0;
		entry = readdir(dir);
		if (entry) {
			if (strcmp(".",entry->d_name) != 0 &&
					strcmp("..",entry->d_name) != 0)
				++count;
		} else {
			CHECK(errno == 0);
			break;
		}
	}
	CHECK(closedir(dir) != -1);
	return count;
}

/* Change to the file system mount directory, check that it is empty,
   matches the file system type, and is not the root file system */
void tests_check_test_file_system(void)
{
	struct statfs fs_info;
	struct stat f_info;
	struct stat root_f_info;

	if (chdir(tests_file_system_mount_dir) == -1 ||
			statfs(tests_file_system_mount_dir, &fs_info) == -1) {
		fprintf(stderr, "Invalid test file system mount directory:"
			" %s\n", tests_file_system_mount_dir);
		fprintf(stderr,	"Use environment variable "
			"TEST_FILE_SYSTEM_MOUNT_DIR\n");
		CHECK(0);
	}
	tests_max_fname_len = fs_info.f_namelen;
	if (strcmp(tests_file_system_type, "jffs2") == 0 &&
			fs_info.f_type != JFFS2_SUPER_MAGIC) {
		fprintf(stderr,	"File system type is not jffs2\n");
		CHECK(0);
	}
	/* Check that the test file system is not the root file system */
	if (!rootok) {
		CHECK(stat(tests_file_system_mount_dir, &f_info) != -1);
		CHECK(stat("/", &root_f_info) != -1);
		CHECK(f_info.st_dev != root_f_info.st_dev);
	}
}

/* Get the free space for the file system of the current directory */
uint64_t tests_get_free_space(void)
{
	struct statvfs fs_info;

	CHECK(statvfs(tests_file_system_mount_dir, &fs_info) != -1);
	return (uint64_t) fs_info.f_bavail * (uint64_t) fs_info.f_frsize;
}

/* Get the total space for the file system of the current directory */
uint64_t tests_get_total_space(void)
{
	struct statvfs fs_info;

	CHECK(statvfs(tests_file_system_mount_dir, &fs_info) != -1);
	return (uint64_t) fs_info.f_blocks * (uint64_t) fs_info.f_frsize;
}

#define WRITE_BUFFER_SIZE 32768

static char write_buffer[WRITE_BUFFER_SIZE];

static void init_write_buffer()
{
	static int init = 0;

	if (!init) {
		int i, d;
		uint64_t u;

		u = RAND_MAX;
		u += 1;
		u /= 256;
		d = (int) u;
		srand(1);
		for (i = 0; i < WRITE_BUFFER_SIZE; ++i)
			write_buffer[i] = rand() / d;
		init = 1;
	}
}

/* Write size random bytes into file descriptor fd at the current position,
   returning the number of bytes actually written */
uint64_t tests_fill_file(int fd, uint64_t size)
{
	ssize_t written;
	size_t sz;
	unsigned start = 0, length;
	uint64_t remains;
	uint64_t actual_size = 0;

	init_write_buffer();
	remains = size;
	while (remains > 0) {
		length = WRITE_BUFFER_SIZE - start;
		if (remains > length)
			sz = length;
		else
			sz = (size_t) remains;
		written = write(fd, write_buffer + start, sz);
		if (written <= 0) {
			CHECK(errno == ENOSPC); /* File system full */
			errno = 0;
			break;
		}
		remains -= written;
		actual_size += written;
		if (written == sz)
			start = 0;
		else
			start += written;
	}
	tests_maybe_sync(fd);
	return actual_size;
}

/* Write size random bytes into file descriptor fd at offset,
   returning the number of bytes actually written */
uint64_t tests_write_filled_file(int fd, off_t offset, uint64_t size)
{
	ssize_t written;
	size_t sz;
	unsigned start = 0, length;
	uint64_t remains;
	uint64_t actual_size = 0;

	CHECK(lseek(fd, offset, SEEK_SET) == offset);

	init_write_buffer();
	remains = size;
	start = offset % WRITE_BUFFER_SIZE;
	while (remains > 0) {
		length = WRITE_BUFFER_SIZE - start;
		if (remains > length)
			sz = length;
		else
			sz = (size_t) remains;
		written = write(fd, write_buffer + start, sz);
		if (written <= 0) {
			CHECK(errno == ENOSPC); /* File system full */
			errno = 0;
			break;
		}
		remains -= written;
		actual_size += written;
		if (written == sz)
			start = 0;
		else
			start += written;
	}
	tests_maybe_sync(fd);
	return actual_size;
}

/* Check that a file written using tests_fill_file() and/or
   tests_write_filled_file() and/or tests_create_file()
   contains the expected random data */
void tests_check_filled_file_fd(int fd)
{
	ssize_t sz;
	char buf[WRITE_BUFFER_SIZE];

	CHECK(lseek(fd, 0, SEEK_SET) == 0);
	do {
		sz = read(fd, buf, WRITE_BUFFER_SIZE);
		CHECK(sz >= 0);
		CHECK(memcmp(buf, write_buffer, sz) == 0);
	} while (sz);
}

/* Check that a file written using tests_fill_file() and/or
   tests_write_filled_file() and/or tests_create_file()
   contains the expected random data */
void tests_check_filled_file(const char *file_name)
{
	int fd;

	fd = open(file_name, O_RDONLY);
	CHECK(fd != -1);
	tests_check_filled_file_fd(fd);
	CHECK(close(fd) != -1);
}

void tests_sync_directory(const char *file_name)
{
	char *path;
	char *dir;
	int fd;

	if (!tests_ok_to_sync)
		return;

	path = strdup(file_name);
	dir = dirname(path);
	fd = open(dir,O_RDONLY | tests_maybe_sync_flag());
	CHECK(fd != -1);
	CHECK(fsync(fd) != -1);
	CHECK(close(fd) != -1);
	free(path);
}

/* Delete a file */
void tests_delete_file(const char *file_name)
{
	CHECK(unlink(file_name) != -1);
	tests_sync_directory(file_name);
}

/* Create a file of size file_size */
uint64_t tests_create_file(const char *file_name, uint64_t file_size)
{
	int fd;
	int flags;
	mode_t mode;
	uint64_t actual_size; /* Less than size if the file system is full */

	flags = O_CREAT | O_TRUNC | O_WRONLY | tests_maybe_sync_flag();
	mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH;
	fd = open(file_name, flags, mode);
	if (fd == -1 && errno == ENOSPC) {
		errno = 0;
		return 0; /* File system full */
	}
	CHECK(fd != -1);
	actual_size = tests_fill_file(fd, file_size);
	CHECK(close(fd) != -1);
	if (file_size != 0 && actual_size == 0)
		tests_delete_file(file_name);
	else
		tests_sync_directory(file_name);
	return actual_size;
}

/* Calculate: free_space * numerator / denominator */
uint64_t tests_get_big_file_size(unsigned numerator, unsigned denominator)
{
	if (denominator == 0)
		denominator = 1;
	if (numerator > denominator)
		numerator = denominator;
	return numerator * (tests_get_free_space() / denominator);
}

/* Create file "fragment_n" where n is the file_number, and unlink it */
int tests_create_orphan(unsigned file_number)
{
	int fd;
	int flags;
	mode_t mode;
	char file_name[256];

	sprintf(file_name, "fragment_%u", file_number);
	flags = O_CREAT | O_TRUNC | O_RDWR | tests_maybe_sync_flag();
	mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH;
	fd = open(file_name, flags, mode);
	if (fd == -1 && (errno == ENOSPC || errno == EMFILE))
		return fd; /* File system full or too many open files */
	CHECK(fd != -1);
	tests_sync_directory(file_name);
	CHECK(unlink(file_name) != -1);
	return fd;
}

/* Write size bytes at offset to the file "fragment_n" where n is the
   file_number and file_number also determines the random data written
   i.e. seed for random numbers */
unsigned tests_write_fragment_file(unsigned file_number,
				int fd,
				off_t offset,
				unsigned size)
{
	int i, d;
	uint64_t u;
	ssize_t written;
	off_t pos;
	char buf[WRITE_BUFFER_SIZE];

	if (size > WRITE_BUFFER_SIZE)
		size = WRITE_BUFFER_SIZE;

	pos = lseek(fd, 0, SEEK_END);
	CHECK(pos != (off_t) -1);
	if (offset > pos)
		offset = pos;

	pos = lseek(fd, offset, SEEK_SET);
	CHECK(pos != (off_t) -1);
	CHECK(pos == offset);

	srand(file_number);
	while (offset--)
		rand();

	u = RAND_MAX;
	u += 1;
	u /= 256;
	d = (int) u;
	for (i = 0; i < size; ++i)
		buf[i] = rand() / d;

	written = write(fd, buf, size);
	if (written <= 0) {
		CHECK(errno == ENOSPC); /* File system full */
		errno = 0;
		written = 0;
	}
	tests_maybe_sync(fd);
	return (unsigned) written;
}

/* Write size bytes to the end of file descriptor fd using file_number
   to determine the random data written i.e. seed for random numbers */
unsigned tests_fill_fragment_file(unsigned file_number, int fd, unsigned size)
{
	off_t offset;

	offset = lseek(fd, 0, SEEK_END);
	CHECK(offset != (off_t) -1);

	return tests_write_fragment_file(file_number, fd, offset, size);
}

/* Write size bytes to the end of file "fragment_n" where n is the file_number
   and file_number also determines the random data written
   i.e. seed for random numbers */
unsigned tests_append_to_fragment_file(unsigned file_number,
					unsigned size,
					int create)
{
	int fd;
	int flags;
	mode_t mode;
	unsigned actual_growth;
	char file_name[256];

	sprintf(file_name, "fragment_%u", file_number);
	if (create)
		flags = O_CREAT | O_EXCL | O_WRONLY | tests_maybe_sync_flag();
	else
		flags = O_WRONLY | tests_maybe_sync_flag();
	mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH;
	fd = open(file_name, flags, mode);
	if (fd == -1 && errno == ENOSPC) {
		errno = 0;
		return 0; /* File system full */
	}
	CHECK(fd != -1);
	actual_growth = tests_fill_fragment_file(file_number, fd, size);
	CHECK(close(fd) != -1);
	if (create && !actual_growth)
		tests_delete_fragment_file(file_number);
	return actual_growth;
}

/* Write size bytes at offset to the file "fragment_n" where n is the
   file_number and file_number also determines the random data written
   i.e. seed for random numbers */
unsigned tests_overwite_fragment_file(	unsigned file_number,
					off_t offset,
					unsigned size)
{
	int fd;
	unsigned actual_size;
	char file_name[256];

	sprintf(file_name, "fragment_%u", file_number);
	fd = open(file_name, O_RDWR | tests_maybe_sync_flag());
	if (fd == -1 && errno == ENOSPC) {
		errno = 0;
		return 0; /* File system full */
	}
	CHECK(fd != -1);
	actual_size = tests_write_fragment_file(file_number,
		fd, offset, size);
	CHECK(close(fd) != -1);
	return actual_size;
}

/* Delete file "fragment_n" where n is the file_number */
void tests_delete_fragment_file(unsigned file_number)
{
	char file_name[256];

	sprintf(file_name, "fragment_%u", file_number);
	tests_delete_file(file_name);
}

/* Check the random data in file "fragment_n" is what is expected */
void tests_check_fragment_file_fd(unsigned file_number, int fd)
{
	ssize_t sz, i;
	int d;
	uint64_t u;
	char buf[8192];

	CHECK(lseek(fd, 0, SEEK_SET) == 0);
	srand(file_number);
	u = RAND_MAX;
	u += 1;
	u /= 256;
	d = (int) u;
	for (;;) {
		sz = read(fd, buf, 8192);
		if (sz == 0)
			break;
		CHECK(sz >= 0);
		for (i = 0; i < sz; ++i)
			CHECK(buf[i] == (char) (rand() / d));
	}
}

/* Check the random data in file "fragment_n" is what is expected */
void tests_check_fragment_file(unsigned file_number)
{
	int fd;
	ssize_t sz, i;
	int d;
	uint64_t u;
	char file_name[256];
	char buf[8192];

	sprintf(file_name, "fragment_%u", file_number);
	fd = open(file_name, O_RDONLY);
	CHECK(fd != -1);
	srand(file_number);
	u = RAND_MAX;
	u += 1;
	u /= 256;
	d = (int) u;
	for (;;) {
		sz = read(fd, buf, 8192);
		if (sz == 0)
			break;
		CHECK(sz >= 0);
		for (i = 0; i < sz; ++i)
			CHECK(buf[i] == (char) (rand() / d));
	}
	CHECK(close(fd) != -1);
}

/* Central point to decide whether to use fsync */
void tests_maybe_sync(int fd)
{
	if (tests_ok_to_sync)
		CHECK(fsync(fd) != -1);
}

/* Return O_SYNC if ok to sync otherwise return 0 */
int tests_maybe_sync_flag(void)
{
	if (tests_ok_to_sync)
		return O_SYNC;
	return 0;
}

/* Return random number from 0 to n - 1 */
size_t tests_random_no(size_t n)
{
	uint64_t a, b;

	if (!n)
		return 0;
	if (n - 1 <= RAND_MAX) {
		a = rand();
		b = RAND_MAX;
		b += 1;
	} else {
		const uint64_t u = 1 + (uint64_t) RAND_MAX;
		a = rand();
		a *= u;
		a += rand();
		b = u * u;
		CHECK(n <= b);
	}
	if (RAND_MAX <= UINT32_MAX && n <= UINT32_MAX)
		return a * n / b;
	else /*if (RAND_MAX <= UINT64_MAX && n <= UINT64_MAX)*/ {
		uint64_t x, y;
		if (a < n) {
			x = a;
			y = n;
		} else {
			x = n;
			y = a;
		}
		return (x * (y / b)) + ((x * (y % b)) / b);
	}
}

/* Make a directory empty */
void tests_clear_dir(const char *dir_name)
{
	DIR *dir;
	struct dirent *entry;
	char buf[4096];

	dir = opendir(dir_name);
	CHECK(dir != NULL);
	CHECK(getcwd(buf, 4096) != NULL);
	CHECK(chdir(dir_name) != -1);
	for (;;) {
		errno = 0;
		entry = readdir(dir);
		if (entry) {
			if (strcmp(".",entry->d_name) != 0 &&
					strcmp("..",entry->d_name) != 0) {
				if (entry->d_type == DT_DIR) {
					tests_clear_dir(entry->d_name);
					CHECK(rmdir(entry->d_name) != -1);
				} else
					CHECK(unlink(entry->d_name) != -1);
			}
		} else {
			CHECK(errno == 0);
			break;
		}
	}
	CHECK(chdir(buf) != -1);
	CHECK(closedir(dir) != -1);
}

/* Create an empty sub-directory or small file in the current directory */
int64_t tests_create_entry(char *return_name)
{
	int fd;
	char name[256];

	for (;;) {
		sprintf(name, "%u", (unsigned) tests_random_no(10000000));
		fd = open(name, O_RDONLY);
		if (fd == -1)
			break;
		close(fd);
	}
	if (return_name)
		strcpy(return_name, name);
	if (tests_random_no(2)) {
		return tests_create_file(name, tests_random_no(4096));
	} else {
		if (mkdir(name, 0777) == -1) {
			CHECK(errno == ENOSPC);
			errno = 0;
			return 0;
		}
		return TESTS_EMPTY_DIR_SIZE;
	}
}

/* Remove a random file of empty sub-directory from the current directory */
int64_t tests_remove_entry(void)
{
	DIR *dir;
	struct dirent *entry;
	unsigned count = 0, pos;
	int64_t result = 0;

	dir = opendir(".");
	CHECK(dir != NULL);
	for (;;) {
		errno = 0;
		entry = readdir(dir);
		if (entry) {
			if (strcmp(".",entry->d_name) != 0 &&
					strcmp("..",entry->d_name) != 0)
				++count;
		} else {
			CHECK(errno == 0);
			break;
		}
	}
	pos = tests_random_no(count);
	count = 0;
	rewinddir(dir);
	for (;;) {
		errno = 0;
		entry = readdir(dir);
		if (!entry) {
			CHECK(errno == 0);
			break;
		}
		if (strcmp(".",entry->d_name) != 0 &&
				strcmp("..",entry->d_name) != 0) {
			if (count == pos) {
				if (entry->d_type == DT_DIR) {
					tests_clear_dir(entry->d_name);
					CHECK(rmdir(entry->d_name) != -1);
					result = TESTS_EMPTY_DIR_SIZE;
				} else {
					struct stat st;
					CHECK(stat(entry->d_name, &st) != -1);
					result = st.st_size;
					CHECK(unlink(entry->d_name) != -1);
				}
			}
			++count;
		}
	}
	CHECK(closedir(dir) != -1);
	return result;
}

/* Read mount information from /proc/mounts or /etc/mtab */
int tests_get_mount_info(struct mntent *info)
{
	FILE *f;
	struct mntent *entry;
	int found = 0;

	f = fopen("/proc/mounts", "rb");
	if (!f)
		f = fopen("/etc/mtab", "rb");
	CHECK(f != NULL);
	while (!found) {
		entry = getmntent(f);
		if (entry) {
			if (strcmp(entry->mnt_dir,
				tests_file_system_mount_dir) == 0) {
				found = 1;
				*info = *entry;
			}
		} else
			break;
	}
	CHECK(fclose(f) == 0);
	return found;
}

/* Un-mount and re-mount test file system */
void tests_remount(void)
{
	struct mntent mount_info;
	char *source;
	char *target;
	char *filesystemtype;
	unsigned long mountflags;
	void *data;
	char cwd[4096];

	CHECK(tests_get_mount_info(&mount_info));

	if (strcmp(mount_info.mnt_dir,"/") == 0)
		return;

	CHECK(getcwd(cwd, 4096) != NULL);
	CHECK(chdir("/") != -1);

	CHECK(umount(tests_file_system_mount_dir) != -1);

	source = mount_info.mnt_fsname;
	target = tests_file_system_mount_dir;
	filesystemtype = tests_file_system_type;
	mountflags = 0;
	data = mount_info.mnt_opts;
	if (data) {
		if (strcmp(data, "rw") == 0)
			data = NULL;
		else if (strncmp(data, "rw,", 3) == 0)
			data += 3;
	}

	CHECK(mount(source, target, filesystemtype, mountflags, data) != -1);

	CHECK(chdir(cwd) != -1);
}

/* Un-mount or re-mount test file system */
static void tests_mnt(int mnt)
{
	static struct mntent mount_info;
	char *source;
	char *target;
	char *filesystemtype;
	unsigned long mountflags;
	void *data;
	static char cwd[4096];

	if (mnt == 0) {
		CHECK(tests_get_mount_info(&mount_info));
		if (strcmp(mount_info.mnt_dir,"/") == 0)
			return;
		CHECK(getcwd(cwd, 4096) != NULL);
		CHECK(chdir("/") != -1);
		CHECK(umount(tests_file_system_mount_dir) != -1);
	} else {
		source = mount_info.mnt_fsname;
		target = tests_file_system_mount_dir;
		filesystemtype = tests_file_system_type;
		mountflags = 0;
		data = NULL;
		CHECK(mount(source, target, filesystemtype, mountflags, data)
			!= -1);
		CHECK(chdir(cwd) != -1);
	}
}

/* Unmount test file system */
void tests_unmount(void)
{
	tests_mnt(0);
}

/* Mount test file system */
void tests_mount(void)
{
	tests_mnt(1);
}

/* Check whether the test file system is also the root file system */
int tests_fs_is_rootfs(void)
{
	struct stat f_info;
	struct stat root_f_info;

	CHECK(stat(tests_file_system_mount_dir, &f_info) != -1);
	CHECK(stat("/", &root_f_info) != -1);
	if (f_info.st_dev == root_f_info.st_dev)
		return 1;
	else
		return 0;
}

/* Try to make a directory empty */
void tests_try_to_clear_dir(const char *dir_name)
{
	DIR *dir;
	struct dirent *entry;
	char buf[4096];

	dir = opendir(dir_name);
	if (dir == NULL)
		return;
	if (getcwd(buf, 4096) == NULL || chdir(dir_name) == -1) {
		closedir(dir);
		return;
	}
	for (;;) {
		errno = 0;
		entry = readdir(dir);
		if (entry) {
			if (strcmp(".",entry->d_name) != 0 &&
					strcmp("..",entry->d_name) != 0) {
				if (entry->d_type == DT_DIR) {
					tests_try_to_clear_dir(entry->d_name);
					rmdir(entry->d_name);
				} else
					unlink(entry->d_name);
			}
		} else {
			CHECK(errno == 0);
			break;
		}
	}
	chdir(buf);
	closedir(dir);
}

/* Check whether the test file system is also the current file system */
int tests_fs_is_currfs(void)
{
	struct stat f_info;
	struct stat curr_f_info;

	CHECK(stat(tests_file_system_mount_dir, &f_info) != -1);
	CHECK(stat(".", &curr_f_info) != -1);
	if (f_info.st_dev == curr_f_info.st_dev)
		return 1;
	else
		return 0;
}

#define PID_BUF_SIZE 64

/* Concatenate a pid to a string in a signal safe way */
void tests_cat_pid(char *buf, const char *name, pid_t pid)
{
	char *p;
	unsigned x;
	const char digits[] = "0123456789";
	char pid_buf[PID_BUF_SIZE];

	x = (unsigned) pid;
	p = pid_buf + PID_BUF_SIZE;
	*--p = '\0';
	if (x)
		while (x) {
			*--p = digits[x % 10];
			x /= 10;
		}
	else
		*--p = '0';
	buf[0] = '\0';
	strcat(buf, name);
	strcat(buf, p);
}