hw/ide/core: Trivial typo fix
[qemu.git] / contrib / ivshmem-client / ivshmem-client.c
1 /*
2 * Copyright 6WIND S.A., 2014
3 *
4 * This work is licensed under the terms of the GNU GPL, version 2 or
5 * (at your option) any later version. See the COPYING file in the
6 * top-level directory.
7 */
8
9 #include "qemu/osdep.h"
10 #include <sys/socket.h>
11 #include <sys/un.h>
12
13 #include "qemu/queue.h"
14
15 #include "ivshmem-client.h"
16
17 /* log a message on stdout if verbose=1 */
18 #define IVSHMEM_CLIENT_DEBUG(client, fmt, ...) do { \
19 if ((client)->verbose) { \
20 printf(fmt, ## __VA_ARGS__); \
21 } \
22 } while (0)
23
24 /* read message from the unix socket */
25 static int
26 ivshmem_client_read_one_msg(IvshmemClient *client, int64_t *index, int *fd)
27 {
28 int ret;
29 struct msghdr msg;
30 struct iovec iov[1];
31 union {
32 struct cmsghdr cmsg;
33 char control[CMSG_SPACE(sizeof(int))];
34 } msg_control;
35 struct cmsghdr *cmsg;
36
37 iov[0].iov_base = index;
38 iov[0].iov_len = sizeof(*index);
39
40 memset(&msg, 0, sizeof(msg));
41 msg.msg_iov = iov;
42 msg.msg_iovlen = 1;
43 msg.msg_control = &msg_control;
44 msg.msg_controllen = sizeof(msg_control);
45
46 ret = recvmsg(client->sock_fd, &msg, 0);
47 if (ret < sizeof(*index)) {
48 IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n",
49 strerror(errno));
50 return -1;
51 }
52 if (ret == 0) {
53 IVSHMEM_CLIENT_DEBUG(client, "lost connection to server\n");
54 return -1;
55 }
56
57 *index = GINT64_FROM_LE(*index);
58 *fd = -1;
59
60 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
61
62 if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
63 cmsg->cmsg_level != SOL_SOCKET ||
64 cmsg->cmsg_type != SCM_RIGHTS) {
65 continue;
66 }
67
68 memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd));
69 }
70
71 return 0;
72 }
73
74 /* free a peer when the server advertises a disconnection or when the
75 * client is freed */
76 static void
77 ivshmem_client_free_peer(IvshmemClient *client, IvshmemClientPeer *peer)
78 {
79 unsigned vector;
80
81 QTAILQ_REMOVE(&client->peer_list, peer, next);
82 for (vector = 0; vector < peer->vectors_count; vector++) {
83 close(peer->vectors[vector]);
84 }
85
86 g_free(peer);
87 }
88
89 /* handle message coming from server (new peer, new vectors) */
90 static int
91 ivshmem_client_handle_server_msg(IvshmemClient *client)
92 {
93 IvshmemClientPeer *peer;
94 int64_t peer_id;
95 int ret, fd;
96
97 ret = ivshmem_client_read_one_msg(client, &peer_id, &fd);
98 if (ret < 0) {
99 return -1;
100 }
101
102 /* can return a peer or the local client */
103 peer = ivshmem_client_search_peer(client, peer_id);
104
105 /* delete peer */
106 if (fd == -1) {
107
108 if (peer == NULL || peer == &client->local) {
109 IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid "
110 "peer %" PRId64 "\n", peer_id);
111 return -1;
112 }
113
114 IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %" PRId64 "\n", peer_id);
115 ivshmem_client_free_peer(client, peer);
116 return 0;
117 }
118
119 /* new peer */
120 if (peer == NULL) {
121 peer = g_malloc0(sizeof(*peer));
122 peer->id = peer_id;
123 peer->vectors_count = 0;
124 QTAILQ_INSERT_TAIL(&client->peer_list, peer, next);
125 IVSHMEM_CLIENT_DEBUG(client, "new peer id = %" PRId64 "\n", peer_id);
126 }
127
128 /* new vector */
129 IVSHMEM_CLIENT_DEBUG(client, " new vector %d (fd=%d) for peer id %"
130 PRId64 "\n", peer->vectors_count, fd, peer->id);
131 if (peer->vectors_count >= G_N_ELEMENTS(peer->vectors)) {
132 IVSHMEM_CLIENT_DEBUG(client, "Too many vectors received, failing");
133 return -1;
134 }
135
136 peer->vectors[peer->vectors_count] = fd;
137 peer->vectors_count++;
138
139 return 0;
140 }
141
142 /* init a new ivshmem client */
143 int
144 ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
145 IvshmemClientNotifCb notif_cb, void *notif_arg,
146 bool verbose)
147 {
148 int ret;
149 unsigned i;
150
151 memset(client, 0, sizeof(*client));
152
153 ret = snprintf(client->unix_sock_path, sizeof(client->unix_sock_path),
154 "%s", unix_sock_path);
155
156 if (ret < 0 || ret >= sizeof(client->unix_sock_path)) {
157 IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
158 return -1;
159 }
160
161 for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
162 client->local.vectors[i] = -1;
163 }
164
165 QTAILQ_INIT(&client->peer_list);
166 client->local.id = -1;
167
168 client->notif_cb = notif_cb;
169 client->notif_arg = notif_arg;
170 client->verbose = verbose;
171 client->shm_fd = -1;
172 client->sock_fd = -1;
173
174 return 0;
175 }
176
177 /* create and connect to the unix socket */
178 int
179 ivshmem_client_connect(IvshmemClient *client)
180 {
181 struct sockaddr_un sun;
182 int fd, ret;
183 int64_t tmp;
184
185 IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n",
186 client->unix_sock_path);
187
188 client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
189 if (client->sock_fd < 0) {
190 IVSHMEM_CLIENT_DEBUG(client, "cannot create socket: %s\n",
191 strerror(errno));
192 return -1;
193 }
194
195 sun.sun_family = AF_UNIX;
196 ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
197 client->unix_sock_path);
198 if (ret < 0 || ret >= sizeof(sun.sun_path)) {
199 IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
200 goto err_close;
201 }
202
203 if (connect(client->sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
204 IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n", sun.sun_path,
205 strerror(errno));
206 goto err_close;
207 }
208
209 /* first, we expect a protocol version */
210 if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
211 (tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) {
212 IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
213 goto err_close;
214 }
215
216 /* then, we expect our index + a fd == -1 */
217 if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 ||
218 client->local.id < 0 || fd != -1) {
219 IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
220 goto err_close;
221 }
222 IVSHMEM_CLIENT_DEBUG(client, "our_id=%" PRId64 "\n", client->local.id);
223
224 /* now, we expect shared mem fd + a -1 index, note that shm fd
225 * is not used */
226 if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
227 tmp != -1 || fd < 0) {
228 if (fd >= 0) {
229 close(fd);
230 }
231 IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n");
232 goto err_close;
233 }
234 client->shm_fd = fd;
235 IVSHMEM_CLIENT_DEBUG(client, "shm_fd=%d\n", fd);
236
237 return 0;
238
239 err_close:
240 close(client->sock_fd);
241 client->sock_fd = -1;
242 return -1;
243 }
244
245 /* close connection to the server, and free all peer structures */
246 void
247 ivshmem_client_close(IvshmemClient *client)
248 {
249 IvshmemClientPeer *peer;
250 unsigned i;
251
252 IVSHMEM_CLIENT_DEBUG(client, "close client\n");
253
254 while ((peer = QTAILQ_FIRST(&client->peer_list)) != NULL) {
255 ivshmem_client_free_peer(client, peer);
256 }
257
258 close(client->shm_fd);
259 client->shm_fd = -1;
260 close(client->sock_fd);
261 client->sock_fd = -1;
262 client->local.id = -1;
263 for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
264 close(client->local.vectors[i]);
265 client->local.vectors[i] = -1;
266 }
267 client->local.vectors_count = 0;
268 }
269
270 /* get the fd_set according to the unix socket and peer list */
271 void
272 ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds, int *maxfd)
273 {
274 int fd;
275 unsigned vector;
276
277 FD_SET(client->sock_fd, fds);
278 if (client->sock_fd >= *maxfd) {
279 *maxfd = client->sock_fd + 1;
280 }
281
282 for (vector = 0; vector < client->local.vectors_count; vector++) {
283 fd = client->local.vectors[vector];
284 FD_SET(fd, fds);
285 if (fd >= *maxfd) {
286 *maxfd = fd + 1;
287 }
288 }
289 }
290
291 /* handle events from eventfd: just print a message on notification */
292 static int
293 ivshmem_client_handle_event(IvshmemClient *client, const fd_set *cur, int maxfd)
294 {
295 IvshmemClientPeer *peer;
296 uint64_t kick;
297 unsigned i;
298 int ret;
299
300 peer = &client->local;
301
302 for (i = 0; i < peer->vectors_count; i++) {
303 if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) {
304 continue;
305 }
306
307 ret = read(peer->vectors[i], &kick, sizeof(kick));
308 if (ret < 0) {
309 return ret;
310 }
311 if (ret != sizeof(kick)) {
312 IVSHMEM_CLIENT_DEBUG(client, "invalid read size = %d\n", ret);
313 errno = EINVAL;
314 return -1;
315 }
316 IVSHMEM_CLIENT_DEBUG(client, "received event on fd %d vector %d: %"
317 PRIu64 "\n", peer->vectors[i], i, kick);
318 if (client->notif_cb != NULL) {
319 client->notif_cb(client, peer, i, client->notif_arg);
320 }
321 }
322
323 return 0;
324 }
325
326 /* read and handle new messages on the given fd_set */
327 int
328 ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd)
329 {
330 if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) &&
331 ivshmem_client_handle_server_msg(client) < 0 && errno != EINTR) {
332 IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_server_msg() "
333 "failed\n");
334 return -1;
335 } else if (ivshmem_client_handle_event(client, fds, maxfd) < 0 &&
336 errno != EINTR) {
337 IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_event() failed\n");
338 return -1;
339 }
340
341 return 0;
342 }
343
344 /* send a notification on a vector of a peer */
345 int
346 ivshmem_client_notify(const IvshmemClient *client,
347 const IvshmemClientPeer *peer, unsigned vector)
348 {
349 uint64_t kick;
350 int fd;
351
352 if (vector >= peer->vectors_count) {
353 IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %" PRId64 "\n",
354 vector, peer->id);
355 return -1;
356 }
357 fd = peer->vectors[vector];
358 IVSHMEM_CLIENT_DEBUG(client, "notify peer %" PRId64
359 " on vector %d, fd %d\n", peer->id, vector, fd);
360
361 kick = 1;
362 if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) {
363 fprintf(stderr, "could not write to %d: %s\n", peer->vectors[vector],
364 strerror(errno));
365 return -1;
366 }
367 return 0;
368 }
369
370 /* send a notification to all vectors of a peer */
371 int
372 ivshmem_client_notify_all_vects(const IvshmemClient *client,
373 const IvshmemClientPeer *peer)
374 {
375 unsigned vector;
376 int ret = 0;
377
378 for (vector = 0; vector < peer->vectors_count; vector++) {
379 if (ivshmem_client_notify(client, peer, vector) < 0) {
380 ret = -1;
381 }
382 }
383
384 return ret;
385 }
386
387 /* send a notification to all peers */
388 int
389 ivshmem_client_notify_broadcast(const IvshmemClient *client)
390 {
391 IvshmemClientPeer *peer;
392 int ret = 0;
393
394 QTAILQ_FOREACH(peer, &client->peer_list, next) {
395 if (ivshmem_client_notify_all_vects(client, peer) < 0) {
396 ret = -1;
397 }
398 }
399
400 return ret;
401 }
402
403 /* lookup peer from its id */
404 IvshmemClientPeer *
405 ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id)
406 {
407 IvshmemClientPeer *peer;
408
409 if (peer_id == client->local.id) {
410 return &client->local;
411 }
412
413 QTAILQ_FOREACH(peer, &client->peer_list, next) {
414 if (peer->id == peer_id) {
415 return peer;
416 }
417 }
418 return NULL;
419 }
420
421 /* dump our info, the list of peers their vectors on stdout */
422 void
423 ivshmem_client_dump(const IvshmemClient *client)
424 {
425 const IvshmemClientPeer *peer;
426 unsigned vector;
427
428 /* dump local infos */
429 peer = &client->local;
430 printf("our_id = %" PRId64 "\n", peer->id);
431 for (vector = 0; vector < peer->vectors_count; vector++) {
432 printf(" vector %d is enabled (fd=%d)\n", vector,
433 peer->vectors[vector]);
434 }
435
436 /* dump peers */
437 QTAILQ_FOREACH(peer, &client->peer_list, next) {
438 printf("peer_id = %" PRId64 "\n", peer->id);
439
440 for (vector = 0; vector < peer->vectors_count; vector++) {
441 printf(" vector %d is enabled (fd=%d)\n", vector,
442 peer->vectors[vector]);
443 }
444 }
445 }