1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * CDDL HEADER START
4 *
5 * The contents of this file are subject to the terms of the
6 * Common Development and Distribution License (the "License").
7 * You may not use this file except in compliance with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or https://opensource.org/licenses/CDDL-1.0.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22
23 /*
24 * Copyright (c) 2021 by Lawrence Livermore National Security, LLC.
25 */
26
27 #include <unistd.h>
28 #include <fcntl.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <sys/mman.h>
33 #include <sys/sysmacros.h>
34 #include <errno.h>
35 #ifdef __linux__
36 #include <linux/fs.h>
37 #endif
38
39 /* some older uClibc's lack the defines, so we'll manually define them */
40 #ifdef __UCLIBC__
41 #ifndef SEEK_DATA
42 #define SEEK_DATA 3
43 #endif
44 #ifndef SEEK_HOLE
45 #define SEEK_HOLE 4
46 #endif
47 #endif
48
49 static void
seek_expect(int fd,off_t offset,int whence,off_t expect_offset)50 seek_expect(int fd, off_t offset, int whence, off_t expect_offset)
51 {
52 errno = 0;
53 off_t seek_offset = lseek(fd, offset, whence);
54 if (seek_offset == expect_offset)
55 return;
56
57 int err = errno;
58 fprintf(stderr, "lseek(fd, %ld, SEEK_%s) = %ld (expected %ld)",
59 offset, (whence == SEEK_DATA ? "DATA" : "HOLE"),
60 seek_offset, expect_offset);
61 if (err != 0)
62 fprintf(stderr, " (errno %d [%s])\n", err, strerror(err));
63 else
64 fputc('\n', stderr);
65 exit(2);
66 }
67
68 static inline void
seek_data(int fd,off_t offset,off_t expected)69 seek_data(int fd, off_t offset, off_t expected)
70 {
71 seek_expect(fd, offset, SEEK_DATA, expected);
72 }
73
74 static inline void
seek_hole(int fd,off_t offset,off_t expected)75 seek_hole(int fd, off_t offset, off_t expected)
76 {
77 seek_expect(fd, offset, SEEK_HOLE, expected);
78 }
79
80 int
main(int argc,char ** argv)81 main(int argc, char **argv)
82 {
83 char *execname = argv[0];
84 char *file_path = argv[1];
85 char *buf = NULL;
86 int err;
87
88 if (argc != 4) {
89 (void) printf("usage: %s <file name> <file size> "
90 "<block size>\n", argv[0]);
91 exit(1);
92 }
93
94 int fd = open(file_path, O_RDWR | O_CREAT, 0666);
95 if (fd == -1) {
96 (void) fprintf(stderr, "%s: %s: ", execname, file_path);
97 perror("open");
98 exit(2);
99 }
100
101 off_t file_size = atoi(argv[2]);
102 off_t block_size = atoi(argv[3]);
103
104 if (block_size * 2 > file_size) {
105 (void) fprintf(stderr, "file size must be at least "
106 "double the block size\n");
107 exit(2);
108 }
109
110 err = ftruncate(fd, file_size);
111 if (err == -1) {
112 perror("ftruncate");
113 exit(2);
114 }
115
116 if ((buf = mmap(NULL, file_size, PROT_READ | PROT_WRITE,
117 MAP_SHARED, fd, 0)) == MAP_FAILED) {
118 perror("mmap");
119 exit(2);
120 }
121
122 /* Verify the file is sparse and reports no data. */
123 seek_data(fd, 0, -1);
124
125 /* Verify the file is reported as a hole. */
126 seek_hole(fd, 0, 0);
127
128 /* Verify search beyond end of file is an error. */
129 seek_data(fd, 2 * file_size, -1);
130 seek_hole(fd, 2 * file_size, -1);
131
132 /* Dirty the first byte. */
133 memset(buf, 'a', 1);
134 seek_data(fd, 0, 0);
135 seek_data(fd, block_size, -1);
136 seek_hole(fd, 0, block_size);
137 seek_hole(fd, block_size, block_size);
138
139 /* Dirty the first half of the file. */
140 memset(buf, 'b', file_size / 2);
141 seek_data(fd, 0, 0);
142 seek_data(fd, block_size, block_size);
143 seek_hole(fd, 0, P2ROUNDUP(file_size / 2, block_size));
144 seek_hole(fd, block_size, P2ROUNDUP(file_size / 2, block_size));
145
146 /* Dirty the whole file. */
147 memset(buf, 'c', file_size);
148 seek_data(fd, 0, 0);
149 seek_data(fd, file_size * 3 / 4,
150 P2ROUNDUP(file_size * 3 / 4, block_size));
151 seek_hole(fd, 0, file_size);
152 seek_hole(fd, file_size / 2, file_size);
153
154 /* Punch a hole (required compression be enabled). */
155 memset(buf + block_size, 0, block_size);
156 seek_data(fd, 0, 0);
157 seek_data(fd, block_size, 2 * block_size);
158 seek_hole(fd, 0, block_size);
159 seek_hole(fd, block_size, block_size);
160 seek_hole(fd, 2 * block_size, file_size);
161
162 err = munmap(buf, file_size);
163 if (err == -1) {
164 perror("munmap");
165 exit(2);
166 }
167
168 close(fd);
169
170 return (0);
171 }
172