1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Simple test program that demonstrates a file copy through io_uring. This
4 * uses the API exposed by liburing.
5 *
6 * Copyright (C) 2018-2019 Jens Axboe
7 */
8 #include <stdio.h>
9 #include <fcntl.h>
10 #include <string.h>
11 #include <stdlib.h>
12 #include <unistd.h>
13 #include <assert.h>
14 #include <errno.h>
15 #include <inttypes.h>
16 #include <sys/types.h>
17 #include <sys/stat.h>
18 #include <sys/ioctl.h>
19
20 #include "liburing.h"
21
22 #define QD 64
23 #define BS (32*1024)
24
25 static int infd, outfd;
26
27 struct io_data {
28 int read;
29 off_t first_offset, offset;
30 size_t first_len;
31 struct iovec iov;
32 };
33
setup_context(unsigned entries,struct io_uring * ring)34 static int setup_context(unsigned entries, struct io_uring *ring)
35 {
36 int ret;
37
38 ret = io_uring_queue_init(entries, ring, 0);
39 if (ret < 0) {
40 fprintf(stderr, "queue_init: %s\n", strerror(-ret));
41 return -1;
42 }
43
44 return 0;
45 }
46
get_file_size(int fd,off_t * size)47 static int get_file_size(int fd, off_t *size)
48 {
49 struct stat st;
50
51 if (fstat(fd, &st) < 0)
52 return -1;
53 if (S_ISREG(st.st_mode)) {
54 *size = st.st_size;
55 return 0;
56 } else if (S_ISBLK(st.st_mode)) {
57 unsigned long long bytes;
58
59 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
60 return -1;
61
62 *size = bytes;
63 return 0;
64 }
65
66 return -1;
67 }
68
queue_prepped(struct io_uring * ring,struct io_data * data)69 static void queue_prepped(struct io_uring *ring, struct io_data *data)
70 {
71 struct io_uring_sqe *sqe;
72
73 sqe = io_uring_get_sqe(ring);
74 assert(sqe);
75
76 if (data->read)
77 io_uring_prep_readv(sqe, infd, &data->iov, 1, data->offset);
78 else
79 io_uring_prep_writev(sqe, outfd, &data->iov, 1, data->offset);
80
81 io_uring_sqe_set_data(sqe, data);
82 }
83
queue_read(struct io_uring * ring,off_t size,off_t offset)84 static int queue_read(struct io_uring *ring, off_t size, off_t offset)
85 {
86 struct io_uring_sqe *sqe;
87 struct io_data *data;
88
89 data = malloc(size + sizeof(*data));
90 if (!data)
91 return 1;
92
93 sqe = io_uring_get_sqe(ring);
94 if (!sqe) {
95 free(data);
96 return 1;
97 }
98
99 data->read = 1;
100 data->offset = data->first_offset = offset;
101
102 data->iov.iov_base = data + 1;
103 data->iov.iov_len = size;
104 data->first_len = size;
105
106 io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
107 io_uring_sqe_set_data(sqe, data);
108 return 0;
109 }
110
queue_write(struct io_uring * ring,struct io_data * data)111 static void queue_write(struct io_uring *ring, struct io_data *data)
112 {
113 data->read = 0;
114 data->offset = data->first_offset;
115
116 data->iov.iov_base = data + 1;
117 data->iov.iov_len = data->first_len;
118
119 queue_prepped(ring, data);
120 io_uring_submit(ring);
121 }
122
copy_file(struct io_uring * ring,off_t insize)123 static int copy_file(struct io_uring *ring, off_t insize)
124 {
125 unsigned long reads, writes;
126 struct io_uring_cqe *cqe;
127 off_t write_left, offset;
128 int ret;
129
130 write_left = insize;
131 writes = reads = offset = 0;
132
133 while (insize || write_left) {
134 int had_reads, got_comp;
135
136 /*
137 * Queue up as many reads as we can
138 */
139 had_reads = reads;
140 while (insize) {
141 off_t this_size = insize;
142
143 if (reads + writes >= QD)
144 break;
145 if (this_size > BS)
146 this_size = BS;
147 else if (!this_size)
148 break;
149
150 if (queue_read(ring, this_size, offset))
151 break;
152
153 insize -= this_size;
154 offset += this_size;
155 reads++;
156 }
157
158 if (had_reads != reads) {
159 ret = io_uring_submit(ring);
160 if (ret < 0) {
161 fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
162 break;
163 }
164 }
165
166 /*
167 * Queue is full at this point. Find at least one completion.
168 */
169 got_comp = 0;
170 while (write_left) {
171 struct io_data *data;
172
173 if (!got_comp) {
174 ret = io_uring_wait_cqe(ring, &cqe);
175 got_comp = 1;
176 } else {
177 ret = io_uring_peek_cqe(ring, &cqe);
178 if (ret == -EAGAIN) {
179 cqe = NULL;
180 ret = 0;
181 }
182 }
183 if (ret < 0) {
184 fprintf(stderr, "io_uring_peek_cqe: %s\n",
185 strerror(-ret));
186 return 1;
187 }
188 if (!cqe)
189 break;
190
191 data = io_uring_cqe_get_data(cqe);
192 if (cqe->res < 0) {
193 if (cqe->res == -EAGAIN) {
194 queue_prepped(ring, data);
195 io_uring_cqe_seen(ring, cqe);
196 continue;
197 }
198 fprintf(stderr, "cqe failed: %s\n",
199 strerror(-cqe->res));
200 return 1;
201 } else if (cqe->res != data->iov.iov_len) {
202 /* Short read/write, adjust and requeue */
203 data->iov.iov_base += cqe->res;
204 data->iov.iov_len -= cqe->res;
205 data->offset += cqe->res;
206 queue_prepped(ring, data);
207 io_uring_cqe_seen(ring, cqe);
208 continue;
209 }
210
211 /*
212 * All done. if write, nothing else to do. if read,
213 * queue up corresponding write.
214 */
215 if (data->read) {
216 queue_write(ring, data);
217 write_left -= data->first_len;
218 reads--;
219 writes++;
220 } else {
221 free(data);
222 writes--;
223 }
224 io_uring_cqe_seen(ring, cqe);
225 }
226 }
227
228 /* wait out pending writes */
229 while (writes) {
230 struct io_data *data;
231
232 ret = io_uring_wait_cqe(ring, &cqe);
233 if (ret) {
234 fprintf(stderr, "wait_cqe=%d\n", ret);
235 return 1;
236 }
237 if (cqe->res < 0) {
238 fprintf(stderr, "write res=%d\n", cqe->res);
239 return 1;
240 }
241 data = io_uring_cqe_get_data(cqe);
242 free(data);
243 writes--;
244 io_uring_cqe_seen(ring, cqe);
245 }
246
247 return 0;
248 }
249
main(int argc,char * argv[])250 int main(int argc, char *argv[])
251 {
252 struct io_uring ring;
253 off_t insize;
254 int ret;
255
256 if (argc < 3) {
257 printf("%s: infile outfile\n", argv[0]);
258 return 1;
259 }
260
261 infd = open(argv[1], O_RDONLY);
262 if (infd < 0) {
263 perror("open infile");
264 return 1;
265 }
266 outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
267 if (outfd < 0) {
268 perror("open outfile");
269 return 1;
270 }
271
272 if (setup_context(QD, &ring))
273 return 1;
274 if (get_file_size(infd, &insize))
275 return 1;
276
277 ret = copy_file(&ring, insize);
278
279 close(infd);
280 close(outfd);
281 io_uring_queue_exit(&ring);
282 return ret;
283 }
284