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hw/9pfs: handle undefined FS_IOC_GETVERSION case in handle_ioc_getversion()
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1 /*
2 * Virtio 9p handle callback
3 *
4 * Copyright IBM, Corp. 2011
5 *
6 * Authors:
7 * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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 */
13
14 #include "hw/virtio/virtio.h"
15 #include "virtio-9p.h"
16 #include "virtio-9p-xattr.h"
17 #include <arpa/inet.h>
18 #include <pwd.h>
19 #include <grp.h>
20 #include <sys/socket.h>
21 #include <sys/un.h>
22 #include "qemu/xattr.h"
23 #include <unistd.h>
24 #include <linux/fs.h>
25 #ifdef CONFIG_LINUX_MAGIC_H
26 #include <linux/magic.h>
27 #endif
28 #include <sys/ioctl.h>
29
30 #ifndef XFS_SUPER_MAGIC
31 #define XFS_SUPER_MAGIC 0x58465342
32 #endif
33 #ifndef EXT2_SUPER_MAGIC
34 #define EXT2_SUPER_MAGIC 0xEF53
35 #endif
36 #ifndef REISERFS_SUPER_MAGIC
37 #define REISERFS_SUPER_MAGIC 0x52654973
38 #endif
39 #ifndef BTRFS_SUPER_MAGIC
40 #define BTRFS_SUPER_MAGIC 0x9123683E
41 #endif
42
43 struct handle_data {
44 int mountfd;
45 int handle_bytes;
46 };
47
48 static inline int name_to_handle(int dirfd, const char *name,
49 struct file_handle *fh, int *mnt_id, int flags)
50 {
51 return name_to_handle_at(dirfd, name, fh, mnt_id, flags);
52 }
53
54 static inline int open_by_handle(int mountfd, const char *fh, int flags)
55 {
56 return open_by_handle_at(mountfd, (struct file_handle *)fh, flags);
57 }
58
59 static int handle_update_file_cred(int dirfd, const char *name, FsCred *credp)
60 {
61 int fd, ret;
62 fd = openat(dirfd, name, O_NONBLOCK | O_NOFOLLOW);
63 if (fd < 0) {
64 return fd;
65 }
66 ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
67 if (ret < 0) {
68 goto err_out;
69 }
70 ret = fchmod(fd, credp->fc_mode & 07777);
71 err_out:
72 close(fd);
73 return ret;
74 }
75
76
77 static int handle_lstat(FsContext *fs_ctx, V9fsPath *fs_path,
78 struct stat *stbuf)
79 {
80 int fd, ret;
81 struct handle_data *data = (struct handle_data *)fs_ctx->private;
82
83 fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
84 if (fd < 0) {
85 return fd;
86 }
87 ret = fstatat(fd, "", stbuf, AT_EMPTY_PATH);
88 close(fd);
89 return ret;
90 }
91
92 static ssize_t handle_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
93 char *buf, size_t bufsz)
94 {
95 int fd, ret;
96 struct handle_data *data = (struct handle_data *)fs_ctx->private;
97
98 fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
99 if (fd < 0) {
100 return fd;
101 }
102 ret = readlinkat(fd, "", buf, bufsz);
103 close(fd);
104 return ret;
105 }
106
107 static int handle_close(FsContext *ctx, V9fsFidOpenState *fs)
108 {
109 return close(fs->fd);
110 }
111
112 static int handle_closedir(FsContext *ctx, V9fsFidOpenState *fs)
113 {
114 return closedir(fs->dir);
115 }
116
117 static int handle_open(FsContext *ctx, V9fsPath *fs_path,
118 int flags, V9fsFidOpenState *fs)
119 {
120 struct handle_data *data = (struct handle_data *)ctx->private;
121
122 fs->fd = open_by_handle(data->mountfd, fs_path->data, flags);
123 return fs->fd;
124 }
125
126 static int handle_opendir(FsContext *ctx,
127 V9fsPath *fs_path, V9fsFidOpenState *fs)
128 {
129 int ret;
130 ret = handle_open(ctx, fs_path, O_DIRECTORY, fs);
131 if (ret < 0) {
132 return -1;
133 }
134 fs->dir = fdopendir(ret);
135 if (!fs->dir) {
136 return -1;
137 }
138 return 0;
139 }
140
141 static void handle_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
142 {
143 return rewinddir(fs->dir);
144 }
145
146 static off_t handle_telldir(FsContext *ctx, V9fsFidOpenState *fs)
147 {
148 return telldir(fs->dir);
149 }
150
151 static int handle_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
152 struct dirent *entry,
153 struct dirent **result)
154 {
155 return readdir_r(fs->dir, entry, result);
156 }
157
158 static void handle_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
159 {
160 return seekdir(fs->dir, off);
161 }
162
163 static ssize_t handle_preadv(FsContext *ctx, V9fsFidOpenState *fs,
164 const struct iovec *iov,
165 int iovcnt, off_t offset)
166 {
167 #ifdef CONFIG_PREADV
168 return preadv(fs->fd, iov, iovcnt, offset);
169 #else
170 int err = lseek(fs->fd, offset, SEEK_SET);
171 if (err == -1) {
172 return err;
173 } else {
174 return readv(fs->fd, iov, iovcnt);
175 }
176 #endif
177 }
178
179 static ssize_t handle_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
180 const struct iovec *iov,
181 int iovcnt, off_t offset)
182 {
183 ssize_t ret;
184 #ifdef CONFIG_PREADV
185 ret = pwritev(fs->fd, iov, iovcnt, offset);
186 #else
187 int err = lseek(fs->fd, offset, SEEK_SET);
188 if (err == -1) {
189 return err;
190 } else {
191 ret = writev(fs->fd, iov, iovcnt);
192 }
193 #endif
194 #ifdef CONFIG_SYNC_FILE_RANGE
195 if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
196 /*
197 * Initiate a writeback. This is not a data integrity sync.
198 * We want to ensure that we don't leave dirty pages in the cache
199 * after write when writeout=immediate is sepcified.
200 */
201 sync_file_range(fs->fd, offset, ret,
202 SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
203 }
204 #endif
205 return ret;
206 }
207
208 static int handle_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
209 {
210 int fd, ret;
211 struct handle_data *data = (struct handle_data *)fs_ctx->private;
212
213 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
214 if (fd < 0) {
215 return fd;
216 }
217 ret = fchmod(fd, credp->fc_mode);
218 close(fd);
219 return ret;
220 }
221
222 static int handle_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
223 const char *name, FsCred *credp)
224 {
225 int dirfd, ret;
226 struct handle_data *data = (struct handle_data *)fs_ctx->private;
227
228 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
229 if (dirfd < 0) {
230 return dirfd;
231 }
232 ret = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
233 if (!ret) {
234 ret = handle_update_file_cred(dirfd, name, credp);
235 }
236 close(dirfd);
237 return ret;
238 }
239
240 static int handle_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
241 const char *name, FsCred *credp)
242 {
243 int dirfd, ret;
244 struct handle_data *data = (struct handle_data *)fs_ctx->private;
245
246 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
247 if (dirfd < 0) {
248 return dirfd;
249 }
250 ret = mkdirat(dirfd, name, credp->fc_mode);
251 if (!ret) {
252 ret = handle_update_file_cred(dirfd, name, credp);
253 }
254 close(dirfd);
255 return ret;
256 }
257
258 static int handle_fstat(FsContext *fs_ctx, int fid_type,
259 V9fsFidOpenState *fs, struct stat *stbuf)
260 {
261 int fd;
262
263 if (fid_type == P9_FID_DIR) {
264 fd = dirfd(fs->dir);
265 } else {
266 fd = fs->fd;
267 }
268 return fstat(fd, stbuf);
269 }
270
271 static int handle_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
272 int flags, FsCred *credp, V9fsFidOpenState *fs)
273 {
274 int ret;
275 int dirfd, fd;
276 struct handle_data *data = (struct handle_data *)fs_ctx->private;
277
278 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
279 if (dirfd < 0) {
280 return dirfd;
281 }
282 fd = openat(dirfd, name, flags | O_NOFOLLOW, credp->fc_mode);
283 if (fd >= 0) {
284 ret = handle_update_file_cred(dirfd, name, credp);
285 if (ret < 0) {
286 close(fd);
287 fd = ret;
288 } else {
289 fs->fd = fd;
290 }
291 }
292 close(dirfd);
293 return fd;
294 }
295
296
297 static int handle_symlink(FsContext *fs_ctx, const char *oldpath,
298 V9fsPath *dir_path, const char *name, FsCred *credp)
299 {
300 int fd, dirfd, ret;
301 struct handle_data *data = (struct handle_data *)fs_ctx->private;
302
303 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
304 if (dirfd < 0) {
305 return dirfd;
306 }
307 ret = symlinkat(oldpath, dirfd, name);
308 if (!ret) {
309 fd = openat(dirfd, name, O_PATH | O_NOFOLLOW);
310 if (fd < 0) {
311 ret = fd;
312 goto err_out;
313 }
314 ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
315 close(fd);
316 }
317 err_out:
318 close(dirfd);
319 return ret;
320 }
321
322 static int handle_link(FsContext *ctx, V9fsPath *oldpath,
323 V9fsPath *dirpath, const char *name)
324 {
325 int oldfd, newdirfd, ret;
326 struct handle_data *data = (struct handle_data *)ctx->private;
327
328 oldfd = open_by_handle(data->mountfd, oldpath->data, O_PATH);
329 if (oldfd < 0) {
330 return oldfd;
331 }
332 newdirfd = open_by_handle(data->mountfd, dirpath->data, O_PATH);
333 if (newdirfd < 0) {
334 close(oldfd);
335 return newdirfd;
336 }
337 ret = linkat(oldfd, "", newdirfd, name, AT_EMPTY_PATH);
338 close(newdirfd);
339 close(oldfd);
340 return ret;
341 }
342
343 static int handle_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
344 {
345 int fd, ret;
346 struct handle_data *data = (struct handle_data *)ctx->private;
347
348 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK | O_WRONLY);
349 if (fd < 0) {
350 return fd;
351 }
352 ret = ftruncate(fd, size);
353 close(fd);
354 return ret;
355 }
356
357 static int handle_rename(FsContext *ctx, const char *oldpath,
358 const char *newpath)
359 {
360 errno = EOPNOTSUPP;
361 return -1;
362 }
363
364 static int handle_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
365 {
366 int fd, ret;
367 struct handle_data *data = (struct handle_data *)fs_ctx->private;
368
369 fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
370 if (fd < 0) {
371 return fd;
372 }
373 ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
374 close(fd);
375 return ret;
376 }
377
378 static int handle_utimensat(FsContext *ctx, V9fsPath *fs_path,
379 const struct timespec *buf)
380 {
381 int ret;
382 #ifdef CONFIG_UTIMENSAT
383 int fd;
384 struct handle_data *data = (struct handle_data *)ctx->private;
385
386 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
387 if (fd < 0) {
388 return fd;
389 }
390 ret = futimens(fd, buf);
391 close(fd);
392 #else
393 ret = -1;
394 errno = ENOSYS;
395 #endif
396 return ret;
397 }
398
399 static int handle_remove(FsContext *ctx, const char *path)
400 {
401 errno = EOPNOTSUPP;
402 return -1;
403 }
404
405 static int handle_fsync(FsContext *ctx, int fid_type,
406 V9fsFidOpenState *fs, int datasync)
407 {
408 int fd;
409
410 if (fid_type == P9_FID_DIR) {
411 fd = dirfd(fs->dir);
412 } else {
413 fd = fs->fd;
414 }
415
416 if (datasync) {
417 return qemu_fdatasync(fd);
418 } else {
419 return fsync(fd);
420 }
421 }
422
423 static int handle_statfs(FsContext *ctx, V9fsPath *fs_path,
424 struct statfs *stbuf)
425 {
426 int fd, ret;
427 struct handle_data *data = (struct handle_data *)ctx->private;
428
429 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
430 if (fd < 0) {
431 return fd;
432 }
433 ret = fstatfs(fd, stbuf);
434 close(fd);
435 return ret;
436 }
437
438 static ssize_t handle_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
439 const char *name, void *value, size_t size)
440 {
441 int fd, ret;
442 struct handle_data *data = (struct handle_data *)ctx->private;
443
444 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
445 if (fd < 0) {
446 return fd;
447 }
448 ret = fgetxattr(fd, name, value, size);
449 close(fd);
450 return ret;
451 }
452
453 static ssize_t handle_llistxattr(FsContext *ctx, V9fsPath *fs_path,
454 void *value, size_t size)
455 {
456 int fd, ret;
457 struct handle_data *data = (struct handle_data *)ctx->private;
458
459 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
460 if (fd < 0) {
461 return fd;
462 }
463 ret = flistxattr(fd, value, size);
464 close(fd);
465 return ret;
466 }
467
468 static int handle_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
469 void *value, size_t size, int flags)
470 {
471 int fd, ret;
472 struct handle_data *data = (struct handle_data *)ctx->private;
473
474 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
475 if (fd < 0) {
476 return fd;
477 }
478 ret = fsetxattr(fd, name, value, size, flags);
479 close(fd);
480 return ret;
481 }
482
483 static int handle_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
484 const char *name)
485 {
486 int fd, ret;
487 struct handle_data *data = (struct handle_data *)ctx->private;
488
489 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
490 if (fd < 0) {
491 return fd;
492 }
493 ret = fremovexattr(fd, name);
494 close(fd);
495 return ret;
496 }
497
498 static int handle_name_to_path(FsContext *ctx, V9fsPath *dir_path,
499 const char *name, V9fsPath *target)
500 {
501 char buffer[PATH_MAX];
502 struct file_handle *fh;
503 int dirfd, ret, mnt_id;
504 struct handle_data *data = (struct handle_data *)ctx->private;
505
506 /* "." and ".." are not allowed */
507 if (!strcmp(name, ".") || !strcmp(name, "..")) {
508 errno = EINVAL;
509 return -1;
510
511 }
512 if (dir_path) {
513 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
514 } else {
515 /* relative to export root */
516 dirfd = open(rpath(ctx, ".", buffer), O_DIRECTORY);
517 }
518 if (dirfd < 0) {
519 return dirfd;
520 }
521 fh = g_malloc(sizeof(struct file_handle) + data->handle_bytes);
522 fh->handle_bytes = data->handle_bytes;
523 /* add a "./" at the beginning of the path */
524 snprintf(buffer, PATH_MAX, "./%s", name);
525 /* flag = 0 imply don't follow symlink */
526 ret = name_to_handle(dirfd, buffer, fh, &mnt_id, 0);
527 if (!ret) {
528 target->data = (char *)fh;
529 target->size = sizeof(struct file_handle) + data->handle_bytes;
530 } else {
531 g_free(fh);
532 }
533 close(dirfd);
534 return ret;
535 }
536
537 static int handle_renameat(FsContext *ctx, V9fsPath *olddir,
538 const char *old_name, V9fsPath *newdir,
539 const char *new_name)
540 {
541 int olddirfd, newdirfd, ret;
542 struct handle_data *data = (struct handle_data *)ctx->private;
543
544 olddirfd = open_by_handle(data->mountfd, olddir->data, O_PATH);
545 if (olddirfd < 0) {
546 return olddirfd;
547 }
548 newdirfd = open_by_handle(data->mountfd, newdir->data, O_PATH);
549 if (newdirfd < 0) {
550 close(olddirfd);
551 return newdirfd;
552 }
553 ret = renameat(olddirfd, old_name, newdirfd, new_name);
554 close(newdirfd);
555 close(olddirfd);
556 return ret;
557 }
558
559 static int handle_unlinkat(FsContext *ctx, V9fsPath *dir,
560 const char *name, int flags)
561 {
562 int dirfd, ret;
563 struct handle_data *data = (struct handle_data *)ctx->private;
564 int rflags;
565
566 dirfd = open_by_handle(data->mountfd, dir->data, O_PATH);
567 if (dirfd < 0) {
568 return dirfd;
569 }
570
571 rflags = 0;
572 if (flags & P9_DOTL_AT_REMOVEDIR) {
573 rflags |= AT_REMOVEDIR;
574 }
575
576 ret = unlinkat(dirfd, name, rflags);
577
578 close(dirfd);
579 return ret;
580 }
581
582 static int handle_ioc_getversion(FsContext *ctx, V9fsPath *path,
583 mode_t st_mode, uint64_t *st_gen)
584 {
585 #ifdef FS_IOC_GETVERSION
586 int err;
587 V9fsFidOpenState fid_open;
588
589 /*
590 * Do not try to open special files like device nodes, fifos etc
591 * We can get fd for regular files and directories only
592 */
593 if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
594 return 0;
595 }
596 err = handle_open(ctx, path, O_RDONLY, &fid_open);
597 if (err < 0) {
598 return err;
599 }
600 err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
601 handle_close(ctx, &fid_open);
602 return err;
603 #else
604 errno = ENOTTY;
605 return -1;
606 #endif
607 }
608
609 static int handle_init(FsContext *ctx)
610 {
611 int ret, mnt_id;
612 struct statfs stbuf;
613 struct file_handle fh;
614 struct handle_data *data = g_malloc(sizeof(struct handle_data));
615
616 data->mountfd = open(ctx->fs_root, O_DIRECTORY);
617 if (data->mountfd < 0) {
618 ret = data->mountfd;
619 goto err_out;
620 }
621 ret = statfs(ctx->fs_root, &stbuf);
622 if (!ret) {
623 switch (stbuf.f_type) {
624 case EXT2_SUPER_MAGIC:
625 case BTRFS_SUPER_MAGIC:
626 case REISERFS_SUPER_MAGIC:
627 case XFS_SUPER_MAGIC:
628 ctx->exops.get_st_gen = handle_ioc_getversion;
629 break;
630 }
631 }
632 memset(&fh, 0, sizeof(struct file_handle));
633 ret = name_to_handle(data->mountfd, ".", &fh, &mnt_id, 0);
634 if (ret && errno == EOVERFLOW) {
635 data->handle_bytes = fh.handle_bytes;
636 ctx->private = data;
637 ret = 0;
638 goto out;
639 }
640 /* we got 0 byte handle ? */
641 ret = -1;
642 close(data->mountfd);
643 err_out:
644 g_free(data);
645 out:
646 return ret;
647 }
648
649 static int handle_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
650 {
651 const char *sec_model = qemu_opt_get(opts, "security_model");
652 const char *path = qemu_opt_get(opts, "path");
653
654 if (sec_model) {
655 fprintf(stderr, "Invalid argument security_model specified with handle fsdriver\n");
656 return -1;
657 }
658
659 if (!path) {
660 fprintf(stderr, "fsdev: No path specified.\n");
661 return -1;
662 }
663 fse->path = g_strdup(path);
664 return 0;
665
666 }
667
668 FileOperations handle_ops = {
669 .parse_opts = handle_parse_opts,
670 .init = handle_init,
671 .lstat = handle_lstat,
672 .readlink = handle_readlink,
673 .close = handle_close,
674 .closedir = handle_closedir,
675 .open = handle_open,
676 .opendir = handle_opendir,
677 .rewinddir = handle_rewinddir,
678 .telldir = handle_telldir,
679 .readdir_r = handle_readdir_r,
680 .seekdir = handle_seekdir,
681 .preadv = handle_preadv,
682 .pwritev = handle_pwritev,
683 .chmod = handle_chmod,
684 .mknod = handle_mknod,
685 .mkdir = handle_mkdir,
686 .fstat = handle_fstat,
687 .open2 = handle_open2,
688 .symlink = handle_symlink,
689 .link = handle_link,
690 .truncate = handle_truncate,
691 .rename = handle_rename,
692 .chown = handle_chown,
693 .utimensat = handle_utimensat,
694 .remove = handle_remove,
695 .fsync = handle_fsync,
696 .statfs = handle_statfs,
697 .lgetxattr = handle_lgetxattr,
698 .llistxattr = handle_llistxattr,
699 .lsetxattr = handle_lsetxattr,
700 .lremovexattr = handle_lremovexattr,
701 .name_to_path = handle_name_to_path,
702 .renameat = handle_renameat,
703 .unlinkat = handle_unlinkat,
704 };