1/*
2 * Copyright 2010 by Garmin Ltd. or its subsidiaries
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 * Performs a simple write/readback test to verify correct functionality
17 * of direct i/o on a block device node.
18 */
19
20/* For large-file support */
21#define _FILE_OFFSET_BITS 64
22#define _LARGEFILE_SOURCE
23#define _LARGEFILE64_SOURCE
24
25/* For O_DIRECT */
26#define _GNU_SOURCE
27
28#include <ctype.h>
29#include <errno.h>
30#include <fcntl.h>
31#include <inttypes.h>
32#include <limits.h>
33#include <stdint.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <sys/ioctl.h>
38#include <sys/mman.h>
39#include <sys/stat.h>
40#include <sys/types.h>
41#include <unistd.h>
42
43#include <linux/fs.h>
44
45#define NUM_TEST_BLKS 128
46
47/*
48 * Allocate page-aligned memory.  Could use posix_memalign(3), but some
49 * systems don't support it.  Also pre-faults memory since we'll be using
50 * it all right away anyway.
51 */
52static void *pagealign_alloc(size_t size)
53{
54	void *ret = mmap(NULL, size, PROT_READ | PROT_WRITE,
55			MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE | MAP_LOCKED,
56			-1, 0);
57	if (ret == MAP_FAILED) {
58		perror("mmap");
59		ret = NULL;
60	}
61	return ret;
62}
63
64static void pagealign_free(void *addr, size_t size)
65{
66	int ret = munmap(addr, size);
67	if (ret == -1)
68		perror("munmap");
69}
70
71static ssize_t do_read(int fd, void *buf, off64_t start, size_t count)
72{
73	ssize_t ret;
74	size_t bytes_read = 0;
75
76	lseek64(fd, start, SEEK_SET);
77
78	do {
79		ret = read(fd, (char *)buf + bytes_read, count - bytes_read);
80		if (ret == -1) {
81			perror("read");
82			return -1;
83		} else if (ret == 0) {
84			fprintf(stderr, "Unexpected end-of-file\n");
85			return -1;
86		}
87		bytes_read += ret;
88	} while (bytes_read < count);
89
90	return bytes_read;
91}
92
93static ssize_t do_write(int fd, const void *buf, off64_t start, size_t count)
94{
95	ssize_t ret;
96	size_t bytes_out = 0;
97
98	lseek64(fd, start, SEEK_SET);
99
100	do {
101		ret = write(fd, (char *)buf + bytes_out, count - bytes_out);
102		if (ret == -1) {
103			perror("write");
104			return -1;
105		} else if (ret == 0) {
106			fprintf(stderr, "write returned 0\n");
107			return -1;
108		}
109		bytes_out += ret;
110	} while (bytes_out < count);
111
112	return bytes_out;
113}
114
115/*
116 * Initializes test buffer with locally-unique test pattern.  High 16-bits of
117 * each 32-bit word contain first disk block number of the test area, low
118 * 16-bits contain word offset into test area.  The goal is that a given test
119 * area should never contain the same data as a nearby test area, and that the
120 * data for a given test area be easily reproducable given the start block and
121 * test area size.
122 */
123static void init_test_buf(void *buf, uint64_t start_blk, size_t len)
124{
125	uint32_t *data = buf;
126	size_t i;
127
128	len /= sizeof(uint32_t);
129	for (i = 0; i < len; i++)
130		data[i] = (start_blk & 0xFFFF) << 16 | (i & 0xFFFF);
131}
132
133static void dump_hex(const void *buf, int len)
134{
135	const uint8_t *data = buf;
136	int i;
137	char ascii_buf[17];
138
139	ascii_buf[16] = '\0';
140
141	for (i = 0; i < len; i++) {
142		int val = data[i];
143		int off = i % 16;
144
145		if (off == 0)
146			printf("%08x  ", i);
147		printf("%02x ", val);
148		ascii_buf[off] = isprint(val) ? val : '.';
149		if (off == 15)
150			printf(" %-16s\n", ascii_buf);
151	}
152
153	i %= 16;
154	if (i) {
155		ascii_buf[i] = '\0';
156		while (i++ < 16)
157			printf("   ");
158		printf(" %-16s\n", ascii_buf);
159	}
160}
161
162static void update_progress(int current, int total)
163{
164	double pct_done = (double)current * 100 / total;
165	printf("Testing area %d/%d (%6.2f%% complete)\r", current, total,
166			pct_done);
167	fflush(stdout);
168}
169
170int main(int argc, const char *argv[])
171{
172	int ret = 1;
173	const char *path;
174	int fd;
175	struct stat stat;
176	void *read_buf = NULL, *write_buf = NULL;
177	int blk_size;
178	uint64_t num_blks;
179	size_t test_size;
180	int test_areas, i;
181
182	if (argc != 2) {
183		printf("Usage: directiotest blkdev_path\n");
184		exit(1);
185	}
186
187	path = argv[1];
188	fd = open(path, O_RDWR | O_DIRECT | O_LARGEFILE);
189	if (fd == -1) {
190		perror("open");
191		exit(1);
192	}
193	if (fstat(fd, &stat) == -1) {
194		perror("stat");
195		goto cleanup;
196	} else if (!S_ISBLK(stat.st_mode)) {
197		fprintf(stderr, "%s is not a block device\n", path);
198		goto cleanup;
199	}
200
201	if (ioctl(fd, BLKSSZGET, &blk_size) == -1) {
202		perror("ioctl");
203		goto cleanup;
204	}
205	if (ioctl(fd, BLKGETSIZE64, &num_blks) == -1) {
206		perror("ioctl");
207		goto cleanup;
208	}
209	num_blks /= blk_size;
210
211	test_size = (size_t)blk_size * NUM_TEST_BLKS;
212	read_buf = pagealign_alloc(test_size);
213	write_buf = pagealign_alloc(test_size);
214	if (!read_buf || !write_buf) {
215		fprintf(stderr, "Error allocating test buffers\n");
216		goto cleanup;
217	}
218
219	/*
220	 * Start the actual test.  Go through the entire device, writing
221	 * locally-unique patern to each test block and then reading it
222	 * back.
223	 */
224	if (num_blks / NUM_TEST_BLKS > INT_MAX) {
225		printf("Warning: Device too large for test variables\n");
226		printf("Entire device will not be tested\n");
227		test_areas = INT_MAX;
228	} else {
229		test_areas = num_blks / NUM_TEST_BLKS;
230	}
231
232	printf("Starting test\n");
233
234	for (i = 0; i < test_areas; i++) {
235		uint64_t cur_blk = (uint64_t)i * NUM_TEST_BLKS;
236
237		update_progress(i + 1, test_areas);
238
239		init_test_buf(write_buf, cur_blk, test_size);
240
241		if (do_write(fd, write_buf, cur_blk * blk_size, test_size) !=
242				(ssize_t)test_size) {
243			fprintf(stderr, "write failed, aborting test\n");
244			goto cleanup;
245		}
246		if (do_read(fd, read_buf, cur_blk * blk_size, test_size) !=
247				(ssize_t)test_size) {
248			fprintf(stderr, "read failed, aborting test\n");
249			goto cleanup;
250		}
251
252		if (memcmp(write_buf, read_buf, test_size)) {
253			printf("Readback verification failed at block %" PRIu64 "\n\n",
254					cur_blk);
255			printf("Written data:\n");
256			dump_hex(write_buf, test_size);
257			printf("\nRead data:\n");
258			dump_hex(read_buf, test_size);
259			goto cleanup;
260		}
261	}
262
263	printf("\nTest complete\n");
264	ret = 0;
265
266cleanup:
267	if (read_buf)
268		pagealign_free(read_buf, test_size);
269	if (write_buf)
270		pagealign_free(write_buf, test_size);
271	close(fd);
272	return ret;
273}
274