vl: Table-based select_vgahw()
[qemu.git] / contrib / ivshmem-server / ivshmem-server.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 #include "qemu/osdep.h"
9 #include "qemu-common.h"
10 #include "qemu/host-utils.h"
11 #include "qemu/sockets.h"
12
13 #include <sys/mman.h>
14 #include <sys/socket.h>
15 #include <sys/un.h>
16
17 #include "ivshmem-server.h"
18
19 /* log a message on stdout if verbose=1 */
20 #define IVSHMEM_SERVER_DEBUG(server, fmt, ...) do { \
21 if ((server)->verbose) { \
22 printf(fmt, ## __VA_ARGS__); \
23 } \
24 } while (0)
25
26 /** maximum size of a huge page, used by ivshmem_server_ftruncate() */
27 #define IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE (1024 * 1024 * 1024)
28
29 /** default listen backlog (number of sockets not accepted) */
30 #define IVSHMEM_SERVER_LISTEN_BACKLOG 10
31
32 /* send message to a client unix socket */
33 static int
34 ivshmem_server_send_one_msg(int sock_fd, int64_t peer_id, int fd)
35 {
36 int ret;
37 struct msghdr msg;
38 struct iovec iov[1];
39 union {
40 struct cmsghdr cmsg;
41 char control[CMSG_SPACE(sizeof(int))];
42 } msg_control;
43 struct cmsghdr *cmsg;
44
45 peer_id = GINT64_TO_LE(peer_id);
46 iov[0].iov_base = &peer_id;
47 iov[0].iov_len = sizeof(peer_id);
48
49 memset(&msg, 0, sizeof(msg));
50 msg.msg_iov = iov;
51 msg.msg_iovlen = 1;
52
53 /* if fd is specified, add it in a cmsg */
54 if (fd >= 0) {
55 memset(&msg_control, 0, sizeof(msg_control));
56 msg.msg_control = &msg_control;
57 msg.msg_controllen = sizeof(msg_control);
58 cmsg = CMSG_FIRSTHDR(&msg);
59 cmsg->cmsg_level = SOL_SOCKET;
60 cmsg->cmsg_type = SCM_RIGHTS;
61 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
62 memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
63 }
64
65 ret = sendmsg(sock_fd, &msg, 0);
66 if (ret <= 0) {
67 return -1;
68 }
69
70 return 0;
71 }
72
73 /* free a peer when the server advertises a disconnection or when the
74 * server is freed */
75 static void
76 ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
77 {
78 unsigned vector;
79 IvshmemServerPeer *other_peer;
80
81 IVSHMEM_SERVER_DEBUG(server, "free peer %" PRId64 "\n", peer->id);
82 close(peer->sock_fd);
83 QTAILQ_REMOVE(&server->peer_list, peer, next);
84
85 /* advertise the deletion to other peers */
86 QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
87 ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id, -1);
88 }
89
90 for (vector = 0; vector < peer->vectors_count; vector++) {
91 event_notifier_cleanup(&peer->vectors[vector]);
92 }
93
94 g_free(peer);
95 }
96
97 /* send the peer id and the shm_fd just after a new client connection */
98 static int
99 ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
100 {
101 int ret;
102
103 /* send our protocol version first */
104 ret = ivshmem_server_send_one_msg(peer->sock_fd, IVSHMEM_PROTOCOL_VERSION,
105 -1);
106 if (ret < 0) {
107 IVSHMEM_SERVER_DEBUG(server, "cannot send version: %s\n",
108 strerror(errno));
109 return -1;
110 }
111
112 /* send the peer id to the client */
113 ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
114 if (ret < 0) {
115 IVSHMEM_SERVER_DEBUG(server, "cannot send peer id: %s\n",
116 strerror(errno));
117 return -1;
118 }
119
120 /* send the shm_fd */
121 ret = ivshmem_server_send_one_msg(peer->sock_fd, -1, server->shm_fd);
122 if (ret < 0) {
123 IVSHMEM_SERVER_DEBUG(server, "cannot send shm fd: %s\n",
124 strerror(errno));
125 return -1;
126 }
127
128 return 0;
129 }
130
131 /* handle message on listening unix socket (new client connection) */
132 static int
133 ivshmem_server_handle_new_conn(IvshmemServer *server)
134 {
135 IvshmemServerPeer *peer, *other_peer;
136 struct sockaddr_un unaddr;
137 socklen_t unaddr_len;
138 int newfd;
139 unsigned i;
140
141 /* accept the incoming connection */
142 unaddr_len = sizeof(unaddr);
143 newfd = qemu_accept(server->sock_fd,
144 (struct sockaddr *)&unaddr, &unaddr_len);
145
146 if (newfd < 0) {
147 IVSHMEM_SERVER_DEBUG(server, "cannot accept() %s\n", strerror(errno));
148 return -1;
149 }
150
151 qemu_set_nonblock(newfd);
152 IVSHMEM_SERVER_DEBUG(server, "accept()=%d\n", newfd);
153
154 /* allocate new structure for this peer */
155 peer = g_malloc0(sizeof(*peer));
156 peer->sock_fd = newfd;
157
158 /* get an unused peer id */
159 /* XXX: this could use id allocation such as Linux IDA, or simply
160 * a free-list */
161 for (i = 0; i < G_MAXUINT16; i++) {
162 if (ivshmem_server_search_peer(server, server->cur_id) == NULL) {
163 break;
164 }
165 server->cur_id++;
166 }
167 if (i == G_MAXUINT16) {
168 IVSHMEM_SERVER_DEBUG(server, "cannot allocate new client id\n");
169 close(newfd);
170 g_free(peer);
171 return -1;
172 }
173 peer->id = server->cur_id++;
174
175 /* create eventfd, one per vector */
176 peer->vectors_count = server->n_vectors;
177 for (i = 0; i < peer->vectors_count; i++) {
178 if (event_notifier_init(&peer->vectors[i], FALSE) < 0) {
179 IVSHMEM_SERVER_DEBUG(server, "cannot create eventfd\n");
180 goto fail;
181 }
182 }
183
184 /* send peer id and shm fd */
185 if (ivshmem_server_send_initial_info(server, peer) < 0) {
186 IVSHMEM_SERVER_DEBUG(server, "cannot send initial info\n");
187 goto fail;
188 }
189
190 /* advertise the new peer to others */
191 QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
192 for (i = 0; i < peer->vectors_count; i++) {
193 ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id,
194 peer->vectors[i].wfd);
195 }
196 }
197
198 /* advertise the other peers to the new one */
199 QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
200 for (i = 0; i < peer->vectors_count; i++) {
201 ivshmem_server_send_one_msg(peer->sock_fd, other_peer->id,
202 other_peer->vectors[i].wfd);
203 }
204 }
205
206 /* advertise the new peer to itself */
207 for (i = 0; i < peer->vectors_count; i++) {
208 ivshmem_server_send_one_msg(peer->sock_fd, peer->id,
209 event_notifier_get_fd(&peer->vectors[i]));
210 }
211
212 QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
213 IVSHMEM_SERVER_DEBUG(server, "new peer id = %" PRId64 "\n",
214 peer->id);
215 return 0;
216
217 fail:
218 while (i--) {
219 event_notifier_cleanup(&peer->vectors[i]);
220 }
221 close(newfd);
222 g_free(peer);
223 return -1;
224 }
225
226 /* Try to ftruncate a file to next power of 2 of shmsize.
227 * If it fails; all power of 2 above shmsize are tested until
228 * we reach the maximum huge page size. This is useful
229 * if the shm file is in a hugetlbfs that cannot be truncated to the
230 * shm_size value. */
231 static int
232 ivshmem_server_ftruncate(int fd, unsigned shmsize)
233 {
234 int ret;
235 struct stat mapstat;
236
237 /* align shmsize to next power of 2 */
238 shmsize = pow2ceil(shmsize);
239
240 if (fstat(fd, &mapstat) != -1 && mapstat.st_size == shmsize) {
241 return 0;
242 }
243
244 while (shmsize <= IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE) {
245 ret = ftruncate(fd, shmsize);
246 if (ret == 0) {
247 return ret;
248 }
249 shmsize *= 2;
250 }
251
252 return -1;
253 }
254
255 /* Init a new ivshmem server */
256 int
257 ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
258 const char *shm_path, bool use_shm_open,
259 size_t shm_size, unsigned n_vectors,
260 bool verbose)
261 {
262 int ret;
263
264 memset(server, 0, sizeof(*server));
265 server->verbose = verbose;
266
267 ret = snprintf(server->unix_sock_path, sizeof(server->unix_sock_path),
268 "%s", unix_sock_path);
269 if (ret < 0 || ret >= sizeof(server->unix_sock_path)) {
270 IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
271 return -1;
272 }
273 ret = snprintf(server->shm_path, sizeof(server->shm_path),
274 "%s", shm_path);
275 if (ret < 0 || ret >= sizeof(server->shm_path)) {
276 IVSHMEM_SERVER_DEBUG(server, "could not copy shm path\n");
277 return -1;
278 }
279
280 server->use_shm_open = use_shm_open;
281 server->shm_size = shm_size;
282 server->n_vectors = n_vectors;
283
284 QTAILQ_INIT(&server->peer_list);
285
286 return 0;
287 }
288
289 /* open shm, create and bind to the unix socket */
290 int
291 ivshmem_server_start(IvshmemServer *server)
292 {
293 struct sockaddr_un sun;
294 int shm_fd, sock_fd, ret;
295
296 /* open shm file */
297 if (server->use_shm_open) {
298 IVSHMEM_SERVER_DEBUG(server, "Using POSIX shared memory: %s\n",
299 server->shm_path);
300 shm_fd = shm_open(server->shm_path, O_CREAT | O_RDWR, S_IRWXU);
301 } else {
302 gchar *filename = g_strdup_printf("%s/ivshmem.XXXXXX", server->shm_path);
303 IVSHMEM_SERVER_DEBUG(server, "Using file-backed shared memory: %s\n",
304 server->shm_path);
305 shm_fd = mkstemp(filename);
306 unlink(filename);
307 g_free(filename);
308 }
309
310 if (shm_fd < 0) {
311 fprintf(stderr, "cannot open shm file %s: %s\n", server->shm_path,
312 strerror(errno));
313 return -1;
314 }
315 if (ivshmem_server_ftruncate(shm_fd, server->shm_size) < 0) {
316 fprintf(stderr, "ftruncate(%s) failed: %s\n", server->shm_path,
317 strerror(errno));
318 goto err_close_shm;
319 }
320
321 IVSHMEM_SERVER_DEBUG(server, "create & bind socket %s\n",
322 server->unix_sock_path);
323
324 /* create the unix listening socket */
325 sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
326 if (sock_fd < 0) {
327 IVSHMEM_SERVER_DEBUG(server, "cannot create socket: %s\n",
328 strerror(errno));
329 goto err_close_shm;
330 }
331
332 sun.sun_family = AF_UNIX;
333 ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
334 server->unix_sock_path);
335 if (ret < 0 || ret >= sizeof(sun.sun_path)) {
336 IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
337 goto err_close_sock;
338 }
339 if (bind(sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
340 IVSHMEM_SERVER_DEBUG(server, "cannot connect to %s: %s\n", sun.sun_path,
341 strerror(errno));
342 goto err_close_sock;
343 }
344
345 if (listen(sock_fd, IVSHMEM_SERVER_LISTEN_BACKLOG) < 0) {
346 IVSHMEM_SERVER_DEBUG(server, "listen() failed: %s\n", strerror(errno));
347 goto err_close_sock;
348 }
349
350 server->sock_fd = sock_fd;
351 server->shm_fd = shm_fd;
352
353 return 0;
354
355 err_close_sock:
356 close(sock_fd);
357 err_close_shm:
358 close(shm_fd);
359 return -1;
360 }
361
362 /* close connections to clients, the unix socket and the shm fd */
363 void
364 ivshmem_server_close(IvshmemServer *server)
365 {
366 IvshmemServerPeer *peer, *npeer;
367
368 IVSHMEM_SERVER_DEBUG(server, "close server\n");
369
370 QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, npeer) {
371 ivshmem_server_free_peer(server, peer);
372 }
373
374 unlink(server->unix_sock_path);
375 close(server->sock_fd);
376 close(server->shm_fd);
377 server->sock_fd = -1;
378 server->shm_fd = -1;
379 }
380
381 /* get the fd_set according to the unix socket and the peer list */
382 void
383 ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd)
384 {
385 IvshmemServerPeer *peer;
386
387 if (server->sock_fd == -1) {
388 return;
389 }
390
391 FD_SET(server->sock_fd, fds);
392 if (server->sock_fd >= *maxfd) {
393 *maxfd = server->sock_fd + 1;
394 }
395
396 QTAILQ_FOREACH(peer, &server->peer_list, next) {
397 FD_SET(peer->sock_fd, fds);
398 if (peer->sock_fd >= *maxfd) {
399 *maxfd = peer->sock_fd + 1;
400 }
401 }
402 }
403
404 /* process incoming messages on the sockets in fd_set */
405 int
406 ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
407 {
408 IvshmemServerPeer *peer, *peer_next;
409
410 if (server->sock_fd < maxfd && FD_ISSET(server->sock_fd, fds) &&
411 ivshmem_server_handle_new_conn(server) < 0 && errno != EINTR) {
412 IVSHMEM_SERVER_DEBUG(server, "ivshmem_server_handle_new_conn() "
413 "failed\n");
414 return -1;
415 }
416
417 QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, peer_next) {
418 /* any message from a peer socket result in a close() */
419 IVSHMEM_SERVER_DEBUG(server, "peer->sock_fd=%d\n", peer->sock_fd);
420 if (peer->sock_fd < maxfd && FD_ISSET(peer->sock_fd, fds)) {
421 ivshmem_server_free_peer(server, peer);
422 }
423 }
424
425 return 0;
426 }
427
428 /* lookup peer from its id */
429 IvshmemServerPeer *
430 ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id)
431 {
432 IvshmemServerPeer *peer;
433
434 QTAILQ_FOREACH(peer, &server->peer_list, next) {
435 if (peer->id == peer_id) {
436 return peer;
437 }
438 }
439 return NULL;
440 }
441
442 /* dump our info, the list of peers their vectors on stdout */
443 void
444 ivshmem_server_dump(const IvshmemServer *server)
445 {
446 const IvshmemServerPeer *peer;
447 unsigned vector;
448
449 /* dump peers */
450 QTAILQ_FOREACH(peer, &server->peer_list, next) {
451 printf("peer_id = %" PRId64 "\n", peer->id);
452
453 for (vector = 0; vector < peer->vectors_count; vector++) {
454 printf(" vector %d is enabled (fd=%d)\n", vector,
455 event_notifier_get_fd(&peer->vectors[vector]));
456 }
457 }
458 }