Fix spelling in comments (intruction -> instruction)
[qemu.git] / block / nbd.c
blob7a52f62e7e1fb0e0af949b6ec3590b78d421ed1d
1 /*
2 * QEMU Block driver for NBD
4 * Copyright (C) 2008 Bull S.A.S.
5 * Author: Laurent Vivier <Laurent.Vivier@bull.net>
7 * Some parts:
8 * Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 * THE SOFTWARE.
29 #include "qemu-common.h"
30 #include "nbd.h"
31 #include "module.h"
32 #include "qemu_socket.h"
34 #include <sys/types.h>
35 #include <unistd.h>
37 #define EN_OPTSTR ":exportname="
39 /* #define DEBUG_NBD */
41 #if defined(DEBUG_NBD)
42 #define logout(fmt, ...) \
43 fprintf(stderr, "nbd\t%-24s" fmt, __func__, ##__VA_ARGS__)
44 #else
45 #define logout(fmt, ...) ((void)0)
46 #endif
48 typedef struct BDRVNBDState {
49 int sock;
50 off_t size;
51 size_t blocksize;
52 char *export_name; /* An NBD server may export several devices */
54 /* If it begins with '/', this is a UNIX domain socket. Otherwise,
55 * it's a string of the form <hostname|ip4|\[ip6\]>:port
57 char *host_spec;
58 } BDRVNBDState;
60 static int nbd_config(BDRVNBDState *s, const char *filename, int flags)
62 char *file;
63 char *export_name;
64 const char *host_spec;
65 const char *unixpath;
66 int err = -EINVAL;
68 file = qemu_strdup(filename);
70 export_name = strstr(file, EN_OPTSTR);
71 if (export_name) {
72 if (export_name[strlen(EN_OPTSTR)] == 0) {
73 goto out;
75 export_name[0] = 0; /* truncate 'file' */
76 export_name += strlen(EN_OPTSTR);
77 s->export_name = qemu_strdup(export_name);
80 /* extract the host_spec - fail if it's not nbd:... */
81 if (!strstart(file, "nbd:", &host_spec)) {
82 goto out;
85 /* are we a UNIX or TCP socket? */
86 if (strstart(host_spec, "unix:", &unixpath)) {
87 if (unixpath[0] != '/') { /* We demand an absolute path*/
88 goto out;
90 s->host_spec = qemu_strdup(unixpath);
91 } else {
92 s->host_spec = qemu_strdup(host_spec);
95 err = 0;
97 out:
98 qemu_free(file);
99 if (err != 0) {
100 qemu_free(s->export_name);
101 qemu_free(s->host_spec);
103 return err;
106 static int nbd_establish_connection(BlockDriverState *bs)
108 BDRVNBDState *s = bs->opaque;
109 int sock;
110 int ret;
111 off_t size;
112 size_t blocksize;
113 uint32_t nbdflags;
115 if (s->host_spec[0] == '/') {
116 sock = unix_socket_outgoing(s->host_spec);
117 } else {
118 sock = tcp_socket_outgoing_spec(s->host_spec);
121 /* Failed to establish connection */
122 if (sock == -1) {
123 logout("Failed to establish connection to NBD server\n");
124 return -errno;
127 /* NBD handshake */
128 ret = nbd_receive_negotiate(sock, s->export_name, &nbdflags, &size,
129 &blocksize);
130 if (ret == -1) {
131 logout("Failed to negotiate with the NBD server\n");
132 closesocket(sock);
133 return -errno;
136 /* Now that we're connected, set the socket to be non-blocking */
137 socket_set_nonblock(sock);
139 s->sock = sock;
140 s->size = size;
141 s->blocksize = blocksize;
143 logout("Established connection with NBD server\n");
144 return 0;
147 static void nbd_teardown_connection(BlockDriverState *bs)
149 BDRVNBDState *s = bs->opaque;
150 struct nbd_request request;
152 request.type = NBD_CMD_DISC;
153 request.handle = (uint64_t)(intptr_t)bs;
154 request.from = 0;
155 request.len = 0;
156 nbd_send_request(s->sock, &request);
158 closesocket(s->sock);
161 static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
163 BDRVNBDState *s = bs->opaque;
164 int result;
166 /* Pop the config into our state object. Exit if invalid. */
167 result = nbd_config(s, filename, flags);
168 if (result != 0) {
169 return result;
172 /* establish TCP connection, return error if it fails
173 * TODO: Configurable retry-until-timeout behaviour.
175 result = nbd_establish_connection(bs);
177 return result;
180 static int nbd_read(BlockDriverState *bs, int64_t sector_num,
181 uint8_t *buf, int nb_sectors)
183 BDRVNBDState *s = bs->opaque;
184 struct nbd_request request;
185 struct nbd_reply reply;
187 request.type = NBD_CMD_READ;
188 request.handle = (uint64_t)(intptr_t)bs;
189 request.from = sector_num * 512;;
190 request.len = nb_sectors * 512;
192 if (nbd_send_request(s->sock, &request) == -1)
193 return -errno;
195 if (nbd_receive_reply(s->sock, &reply) == -1)
196 return -errno;
198 if (reply.error !=0)
199 return -reply.error;
201 if (reply.handle != request.handle)
202 return -EIO;
204 if (nbd_wr_sync(s->sock, buf, request.len, 1) != request.len)
205 return -EIO;
207 return 0;
210 static int nbd_write(BlockDriverState *bs, int64_t sector_num,
211 const uint8_t *buf, int nb_sectors)
213 BDRVNBDState *s = bs->opaque;
214 struct nbd_request request;
215 struct nbd_reply reply;
217 request.type = NBD_CMD_WRITE;
218 request.handle = (uint64_t)(intptr_t)bs;
219 request.from = sector_num * 512;;
220 request.len = nb_sectors * 512;
222 if (nbd_send_request(s->sock, &request) == -1)
223 return -errno;
225 if (nbd_wr_sync(s->sock, (uint8_t*)buf, request.len, 0) != request.len)
226 return -EIO;
228 if (nbd_receive_reply(s->sock, &reply) == -1)
229 return -errno;
231 if (reply.error !=0)
232 return -reply.error;
234 if (reply.handle != request.handle)
235 return -EIO;
237 return 0;
240 static void nbd_close(BlockDriverState *bs)
242 BDRVNBDState *s = bs->opaque;
243 qemu_free(s->export_name);
244 qemu_free(s->host_spec);
246 nbd_teardown_connection(bs);
249 static int64_t nbd_getlength(BlockDriverState *bs)
251 BDRVNBDState *s = bs->opaque;
253 return s->size;
256 static BlockDriver bdrv_nbd = {
257 .format_name = "nbd",
258 .instance_size = sizeof(BDRVNBDState),
259 .bdrv_file_open = nbd_open,
260 .bdrv_read = nbd_read,
261 .bdrv_write = nbd_write,
262 .bdrv_close = nbd_close,
263 .bdrv_getlength = nbd_getlength,
264 .protocol_name = "nbd",
267 static void bdrv_nbd_init(void)
269 bdrv_register(&bdrv_nbd);
272 block_init(bdrv_nbd_init);