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4c793dda MK |
1 | /* |
2 | * Virtio 9p Proxy callback | |
3 | * | |
4 | * Copyright IBM, Corp. 2011 | |
5 | * | |
6 | * Authors: | |
7 | * M. Mohan Kumar <mohan@in.ibm.com> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
10 | * the COPYING file in the top-level directory. | |
11 | */ | |
12 | #include <sys/socket.h> | |
13 | #include <sys/un.h> | |
14 | #include "hw/virtio.h" | |
15 | #include "virtio-9p.h" | |
16 | #include "fsdev/qemu-fsdev.h" | |
17 | #include "virtio-9p-proxy.h" | |
18 | ||
19 | typedef struct V9fsProxy { | |
20 | int sockfd; | |
21 | QemuMutex mutex; | |
22 | struct iovec iovec; | |
23 | } V9fsProxy; | |
24 | ||
daf0b9ac MK |
25 | /* |
26 | * Return received file descriptor on success in *status. | |
27 | * errno is also returned on *status (which will be < 0) | |
28 | * return < 0 on transport error. | |
29 | */ | |
30 | static int v9fs_receivefd(int sockfd, int *status) | |
31 | { | |
32 | struct iovec iov; | |
33 | struct msghdr msg; | |
34 | struct cmsghdr *cmsg; | |
35 | int retval, data, fd; | |
36 | union MsgControl msg_control; | |
37 | ||
38 | iov.iov_base = &data; | |
39 | iov.iov_len = sizeof(data); | |
40 | ||
41 | memset(&msg, 0, sizeof(msg)); | |
42 | msg.msg_iov = &iov; | |
43 | msg.msg_iovlen = 1; | |
44 | msg.msg_control = &msg_control; | |
45 | msg.msg_controllen = sizeof(msg_control); | |
46 | ||
47 | do { | |
48 | retval = recvmsg(sockfd, &msg, 0); | |
49 | } while (retval < 0 && errno == EINTR); | |
50 | if (retval <= 0) { | |
51 | return retval; | |
52 | } | |
53 | /* | |
54 | * data is set to V9FS_FD_VALID, if ancillary data is sent. If this | |
55 | * request doesn't need ancillary data (fd) or an error occurred, | |
56 | * data is set to negative errno value. | |
57 | */ | |
58 | if (data != V9FS_FD_VALID) { | |
59 | *status = data; | |
60 | return 0; | |
61 | } | |
62 | /* | |
63 | * File descriptor (fd) is sent in the ancillary data. Check if we | |
64 | * indeed received it. One of the reasons to fail to receive it is if | |
65 | * we exceeded the maximum number of file descriptors! | |
66 | */ | |
67 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { | |
68 | if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) || | |
69 | cmsg->cmsg_level != SOL_SOCKET || | |
70 | cmsg->cmsg_type != SCM_RIGHTS) { | |
71 | continue; | |
72 | } | |
73 | fd = *((int *)CMSG_DATA(cmsg)); | |
74 | *status = fd; | |
75 | return 0; | |
76 | } | |
77 | *status = -ENFILE; /* Ancillary data sent but not received */ | |
78 | return 0; | |
79 | } | |
80 | ||
81 | /* | |
82 | * Proxy->header and proxy->request written to socket by QEMU process. | |
83 | * This request read by proxy helper process | |
84 | * returns 0 on success and -errno on error | |
85 | */ | |
86 | static int v9fs_request(V9fsProxy *proxy, int type, | |
87 | void *response, const char *fmt, ...) | |
88 | { | |
89 | va_list ap; | |
90 | int retval = 0; | |
91 | V9fsString *path; | |
92 | ProxyHeader header = { 0, 0}; | |
93 | struct iovec *iovec = NULL; | |
94 | int flags, mode, uid, gid; | |
95 | ||
96 | qemu_mutex_lock(&proxy->mutex); | |
97 | ||
98 | if (proxy->sockfd == -1) { | |
99 | retval = -EIO; | |
100 | goto err_out; | |
101 | } | |
102 | iovec = &proxy->iovec; | |
103 | ||
104 | va_start(ap, fmt); | |
105 | switch (type) { | |
106 | case T_OPEN: | |
107 | path = va_arg(ap, V9fsString *); | |
108 | flags = va_arg(ap, int); | |
109 | retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sd", path, flags); | |
110 | if (retval > 0) { | |
111 | header.size = retval; | |
112 | header.type = T_OPEN; | |
113 | } | |
114 | break; | |
115 | case T_CREATE: | |
116 | path = va_arg(ap, V9fsString *); | |
117 | flags = va_arg(ap, int); | |
118 | mode = va_arg(ap, int); | |
119 | uid = va_arg(ap, int); | |
120 | gid = va_arg(ap, int); | |
121 | retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sdddd", path, | |
122 | flags, mode, uid, gid); | |
123 | if (retval > 0) { | |
124 | header.size = retval; | |
125 | header.type = T_CREATE; | |
126 | } | |
127 | break; | |
128 | default: | |
129 | error_report("Invalid type %d\n", type); | |
130 | retval = -EINVAL; | |
131 | break; | |
132 | } | |
133 | va_end(ap); | |
134 | ||
135 | if (retval < 0) { | |
136 | goto err_out; | |
137 | } | |
138 | ||
139 | /* marshal the header details */ | |
140 | proxy_marshal(iovec, 0, "dd", header.type, header.size); | |
141 | header.size += PROXY_HDR_SZ; | |
142 | ||
143 | retval = qemu_write_full(proxy->sockfd, iovec->iov_base, header.size); | |
144 | if (retval != header.size) { | |
145 | goto close_error; | |
146 | } | |
147 | ||
148 | switch (type) { | |
149 | case T_OPEN: | |
150 | case T_CREATE: | |
151 | /* | |
152 | * A file descriptor is returned as response for | |
153 | * T_OPEN,T_CREATE on success | |
154 | */ | |
155 | if (v9fs_receivefd(proxy->sockfd, &retval) < 0) { | |
156 | goto close_error; | |
157 | } | |
158 | break; | |
159 | } | |
160 | ||
161 | err_out: | |
162 | qemu_mutex_unlock(&proxy->mutex); | |
163 | return retval; | |
164 | ||
165 | close_error: | |
166 | close(proxy->sockfd); | |
167 | proxy->sockfd = -1; | |
168 | qemu_mutex_unlock(&proxy->mutex); | |
169 | return -EIO; | |
170 | } | |
171 | ||
4c793dda MK |
172 | static int proxy_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf) |
173 | { | |
174 | errno = EOPNOTSUPP; | |
175 | return -1; | |
176 | } | |
177 | ||
178 | static ssize_t proxy_readlink(FsContext *fs_ctx, V9fsPath *fs_path, | |
179 | char *buf, size_t bufsz) | |
180 | { | |
181 | errno = EOPNOTSUPP; | |
182 | return -1; | |
183 | } | |
184 | ||
185 | static int proxy_close(FsContext *ctx, V9fsFidOpenState *fs) | |
186 | { | |
187 | return close(fs->fd); | |
188 | } | |
189 | ||
190 | static int proxy_closedir(FsContext *ctx, V9fsFidOpenState *fs) | |
191 | { | |
192 | return closedir(fs->dir); | |
193 | } | |
194 | ||
195 | static int proxy_open(FsContext *ctx, V9fsPath *fs_path, | |
196 | int flags, V9fsFidOpenState *fs) | |
197 | { | |
daf0b9ac MK |
198 | fs->fd = v9fs_request(ctx->private, T_OPEN, NULL, "sd", fs_path, flags); |
199 | if (fs->fd < 0) { | |
200 | errno = -fs->fd; | |
201 | fs->fd = -1; | |
202 | } | |
4c793dda MK |
203 | return fs->fd; |
204 | } | |
205 | ||
206 | static int proxy_opendir(FsContext *ctx, | |
207 | V9fsPath *fs_path, V9fsFidOpenState *fs) | |
208 | { | |
daf0b9ac MK |
209 | int serrno, fd; |
210 | ||
4c793dda | 211 | fs->dir = NULL; |
daf0b9ac MK |
212 | fd = v9fs_request(ctx->private, T_OPEN, NULL, "sd", fs_path, O_DIRECTORY); |
213 | if (fd < 0) { | |
214 | errno = -fd; | |
215 | return -1; | |
216 | } | |
217 | fs->dir = fdopendir(fd); | |
218 | if (!fs->dir) { | |
219 | serrno = errno; | |
220 | close(fd); | |
221 | errno = serrno; | |
222 | return -1; | |
223 | } | |
224 | return 0; | |
4c793dda MK |
225 | } |
226 | ||
227 | static void proxy_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) | |
228 | { | |
229 | return rewinddir(fs->dir); | |
230 | } | |
231 | ||
232 | static off_t proxy_telldir(FsContext *ctx, V9fsFidOpenState *fs) | |
233 | { | |
234 | return telldir(fs->dir); | |
235 | } | |
236 | ||
237 | static int proxy_readdir_r(FsContext *ctx, V9fsFidOpenState *fs, | |
238 | struct dirent *entry, | |
239 | struct dirent **result) | |
240 | { | |
241 | return readdir_r(fs->dir, entry, result); | |
242 | } | |
243 | ||
244 | static void proxy_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) | |
245 | { | |
246 | return seekdir(fs->dir, off); | |
247 | } | |
248 | ||
249 | static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs, | |
250 | const struct iovec *iov, | |
251 | int iovcnt, off_t offset) | |
252 | { | |
253 | #ifdef CONFIG_PREADV | |
254 | return preadv(fs->fd, iov, iovcnt, offset); | |
255 | #else | |
256 | int err = lseek(fs->fd, offset, SEEK_SET); | |
257 | if (err == -1) { | |
258 | return err; | |
259 | } else { | |
260 | return readv(fs->fd, iov, iovcnt); | |
261 | } | |
262 | #endif | |
263 | } | |
264 | ||
265 | static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs, | |
266 | const struct iovec *iov, | |
267 | int iovcnt, off_t offset) | |
268 | { | |
269 | ssize_t ret; | |
270 | ||
271 | #ifdef CONFIG_PREADV | |
272 | ret = pwritev(fs->fd, iov, iovcnt, offset); | |
273 | #else | |
274 | int err = lseek(fs->fd, offset, SEEK_SET); | |
275 | if (err == -1) { | |
276 | return err; | |
277 | } else { | |
278 | ret = writev(fs->fd, iov, iovcnt); | |
279 | } | |
280 | #endif | |
281 | #ifdef CONFIG_SYNC_FILE_RANGE | |
282 | if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) { | |
283 | /* | |
284 | * Initiate a writeback. This is not a data integrity sync. | |
285 | * We want to ensure that we don't leave dirty pages in the cache | |
286 | * after write when writeout=immediate is sepcified. | |
287 | */ | |
288 | sync_file_range(fs->fd, offset, ret, | |
289 | SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE); | |
290 | } | |
291 | #endif | |
292 | return ret; | |
293 | } | |
294 | ||
295 | static int proxy_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) | |
296 | { | |
297 | errno = EOPNOTSUPP; | |
298 | return -1; | |
299 | } | |
300 | ||
301 | static int proxy_mknod(FsContext *fs_ctx, V9fsPath *dir_path, | |
302 | const char *name, FsCred *credp) | |
303 | { | |
304 | errno = EOPNOTSUPP; | |
305 | return -1; | |
306 | } | |
307 | ||
308 | static int proxy_mkdir(FsContext *fs_ctx, V9fsPath *dir_path, | |
309 | const char *name, FsCred *credp) | |
310 | { | |
311 | errno = EOPNOTSUPP; | |
312 | return -1; | |
313 | } | |
314 | ||
315 | static int proxy_fstat(FsContext *fs_ctx, int fid_type, | |
316 | V9fsFidOpenState *fs, struct stat *stbuf) | |
317 | { | |
318 | int fd; | |
319 | ||
320 | if (fid_type == P9_FID_DIR) { | |
321 | fd = dirfd(fs->dir); | |
322 | } else { | |
323 | fd = fs->fd; | |
324 | } | |
325 | return fstat(fd, stbuf); | |
326 | } | |
327 | ||
328 | static int proxy_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, | |
329 | int flags, FsCred *credp, V9fsFidOpenState *fs) | |
330 | { | |
daf0b9ac MK |
331 | V9fsString fullname; |
332 | ||
333 | v9fs_string_init(&fullname); | |
334 | v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name); | |
335 | ||
336 | fs->fd = v9fs_request(fs_ctx->private, T_CREATE, NULL, "sdddd", | |
337 | &fullname, flags, credp->fc_mode, | |
338 | credp->fc_uid, credp->fc_gid); | |
339 | v9fs_string_free(&fullname); | |
340 | if (fs->fd < 0) { | |
341 | errno = -fs->fd; | |
342 | fs->fd = -1; | |
343 | } | |
344 | return fs->fd; | |
4c793dda MK |
345 | } |
346 | ||
347 | ||
348 | static int proxy_symlink(FsContext *fs_ctx, const char *oldpath, | |
349 | V9fsPath *dir_path, const char *name, FsCred *credp) | |
350 | { | |
351 | errno = EOPNOTSUPP; | |
352 | return -1; | |
353 | } | |
354 | ||
355 | static int proxy_link(FsContext *ctx, V9fsPath *oldpath, | |
356 | V9fsPath *dirpath, const char *name) | |
357 | { | |
358 | errno = EOPNOTSUPP; | |
359 | return -1; | |
360 | } | |
361 | ||
362 | static int proxy_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size) | |
363 | { | |
364 | errno = EOPNOTSUPP; | |
365 | return -1; | |
366 | } | |
367 | ||
368 | static int proxy_rename(FsContext *ctx, const char *oldpath, | |
369 | const char *newpath) | |
370 | { | |
371 | errno = EOPNOTSUPP; | |
372 | return -1; | |
373 | } | |
374 | ||
375 | static int proxy_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) | |
376 | { | |
377 | errno = EOPNOTSUPP; | |
378 | return -1; | |
379 | } | |
380 | ||
381 | static int proxy_utimensat(FsContext *s, V9fsPath *fs_path, | |
382 | const struct timespec *buf) | |
383 | { | |
384 | errno = EOPNOTSUPP; | |
385 | return -1; | |
386 | } | |
387 | ||
388 | static int proxy_remove(FsContext *ctx, const char *path) | |
389 | { | |
390 | errno = EOPNOTSUPP; | |
391 | return -1; | |
392 | } | |
393 | ||
394 | static int proxy_fsync(FsContext *ctx, int fid_type, | |
395 | V9fsFidOpenState *fs, int datasync) | |
396 | { | |
397 | int fd; | |
398 | ||
399 | if (fid_type == P9_FID_DIR) { | |
400 | fd = dirfd(fs->dir); | |
401 | } else { | |
402 | fd = fs->fd; | |
403 | } | |
404 | ||
405 | if (datasync) { | |
406 | return qemu_fdatasync(fd); | |
407 | } else { | |
408 | return fsync(fd); | |
409 | } | |
410 | } | |
411 | ||
412 | static int proxy_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) | |
413 | { | |
414 | errno = EOPNOTSUPP; | |
415 | return -1; | |
416 | } | |
417 | ||
418 | static ssize_t proxy_lgetxattr(FsContext *ctx, V9fsPath *fs_path, | |
419 | const char *name, void *value, size_t size) | |
420 | { | |
421 | errno = EOPNOTSUPP; | |
422 | return -1; | |
423 | } | |
424 | ||
425 | static ssize_t proxy_llistxattr(FsContext *ctx, V9fsPath *fs_path, | |
426 | void *value, size_t size) | |
427 | { | |
428 | errno = EOPNOTSUPP; | |
429 | return -1; | |
430 | } | |
431 | ||
432 | static int proxy_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name, | |
433 | void *value, size_t size, int flags) | |
434 | { | |
435 | errno = EOPNOTSUPP; | |
436 | return -1; | |
437 | } | |
438 | ||
439 | static int proxy_lremovexattr(FsContext *ctx, V9fsPath *fs_path, | |
440 | const char *name) | |
441 | { | |
442 | errno = EOPNOTSUPP; | |
443 | return -1; | |
444 | } | |
445 | ||
446 | static int proxy_name_to_path(FsContext *ctx, V9fsPath *dir_path, | |
447 | const char *name, V9fsPath *target) | |
448 | { | |
449 | if (dir_path) { | |
450 | v9fs_string_sprintf((V9fsString *)target, "%s/%s", | |
451 | dir_path->data, name); | |
452 | } else { | |
453 | v9fs_string_sprintf((V9fsString *)target, "%s", name); | |
454 | } | |
455 | /* Bump the size for including terminating NULL */ | |
456 | target->size++; | |
457 | return 0; | |
458 | } | |
459 | ||
460 | static int proxy_renameat(FsContext *ctx, V9fsPath *olddir, | |
461 | const char *old_name, V9fsPath *newdir, | |
462 | const char *new_name) | |
463 | { | |
464 | int ret; | |
465 | V9fsString old_full_name, new_full_name; | |
466 | ||
467 | v9fs_string_init(&old_full_name); | |
468 | v9fs_string_init(&new_full_name); | |
469 | ||
470 | v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name); | |
471 | v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name); | |
472 | ||
473 | ret = proxy_rename(ctx, old_full_name.data, new_full_name.data); | |
474 | v9fs_string_free(&old_full_name); | |
475 | v9fs_string_free(&new_full_name); | |
476 | return ret; | |
477 | } | |
478 | ||
479 | static int proxy_unlinkat(FsContext *ctx, V9fsPath *dir, | |
480 | const char *name, int flags) | |
481 | { | |
482 | int ret; | |
483 | V9fsString fullname; | |
484 | v9fs_string_init(&fullname); | |
485 | ||
486 | v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name); | |
487 | ret = proxy_remove(ctx, fullname.data); | |
488 | v9fs_string_free(&fullname); | |
489 | ||
490 | return ret; | |
491 | } | |
492 | ||
493 | static int proxy_parse_opts(QemuOpts *opts, struct FsDriverEntry *fs) | |
494 | { | |
495 | const char *sock_fd = qemu_opt_get(opts, "sock_fd"); | |
496 | ||
497 | if (sock_fd) { | |
498 | fprintf(stderr, "sock_fd option not specified\n"); | |
499 | return -1; | |
500 | } | |
501 | fs->path = g_strdup(sock_fd); | |
502 | return 0; | |
503 | } | |
504 | ||
505 | static int proxy_init(FsContext *ctx) | |
506 | { | |
507 | V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy)); | |
508 | int sock_id; | |
509 | ||
510 | sock_id = atoi(ctx->fs_root); | |
511 | if (sock_id < 0) { | |
512 | fprintf(stderr, "socket descriptor not initialized\n"); | |
513 | return -1; | |
514 | } | |
515 | g_free(ctx->fs_root); | |
516 | ||
517 | proxy->iovec.iov_base = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ); | |
518 | proxy->iovec.iov_len = PROXY_MAX_IO_SZ + PROXY_HDR_SZ; | |
519 | ctx->private = proxy; | |
520 | proxy->sockfd = sock_id; | |
521 | qemu_mutex_init(&proxy->mutex); | |
522 | ||
523 | ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT; | |
524 | return 0; | |
525 | } | |
526 | ||
527 | FileOperations proxy_ops = { | |
528 | .parse_opts = proxy_parse_opts, | |
529 | .init = proxy_init, | |
530 | .lstat = proxy_lstat, | |
531 | .readlink = proxy_readlink, | |
532 | .close = proxy_close, | |
533 | .closedir = proxy_closedir, | |
534 | .open = proxy_open, | |
535 | .opendir = proxy_opendir, | |
536 | .rewinddir = proxy_rewinddir, | |
537 | .telldir = proxy_telldir, | |
538 | .readdir_r = proxy_readdir_r, | |
539 | .seekdir = proxy_seekdir, | |
540 | .preadv = proxy_preadv, | |
541 | .pwritev = proxy_pwritev, | |
542 | .chmod = proxy_chmod, | |
543 | .mknod = proxy_mknod, | |
544 | .mkdir = proxy_mkdir, | |
545 | .fstat = proxy_fstat, | |
546 | .open2 = proxy_open2, | |
547 | .symlink = proxy_symlink, | |
548 | .link = proxy_link, | |
549 | .truncate = proxy_truncate, | |
550 | .rename = proxy_rename, | |
551 | .chown = proxy_chown, | |
552 | .utimensat = proxy_utimensat, | |
553 | .remove = proxy_remove, | |
554 | .fsync = proxy_fsync, | |
555 | .statfs = proxy_statfs, | |
556 | .lgetxattr = proxy_lgetxattr, | |
557 | .llistxattr = proxy_llistxattr, | |
558 | .lsetxattr = proxy_lsetxattr, | |
559 | .lremovexattr = proxy_lremovexattr, | |
560 | .name_to_path = proxy_name_to_path, | |
561 | .renameat = proxy_renameat, | |
562 | .unlinkat = proxy_unlinkat, | |
563 | }; |