9pfs: add cleanup operation for handle backend driver
[qemu.git] / hw / 9pfs / 9p-handle.c
1 /*
2 * 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 "qemu/osdep.h"
15 #include "9p.h"
16 #include "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 "qemu/cutils.h"
24 #include "qemu/error-report.h"
25 #include <linux/fs.h>
26 #ifdef CONFIG_LINUX_MAGIC_H
27 #include <linux/magic.h>
28 #endif
29 #include <sys/ioctl.h>
30
31 #ifndef XFS_SUPER_MAGIC
32 #define XFS_SUPER_MAGIC 0x58465342
33 #endif
34 #ifndef EXT2_SUPER_MAGIC
35 #define EXT2_SUPER_MAGIC 0xEF53
36 #endif
37 #ifndef REISERFS_SUPER_MAGIC
38 #define REISERFS_SUPER_MAGIC 0x52654973
39 #endif
40 #ifndef BTRFS_SUPER_MAGIC
41 #define BTRFS_SUPER_MAGIC 0x9123683E
42 #endif
43
44 struct handle_data {
45 int mountfd;
46 int handle_bytes;
47 };
48
49 static inline int name_to_handle(int dirfd, const char *name,
50 struct file_handle *fh, int *mnt_id, int flags)
51 {
52 return name_to_handle_at(dirfd, name, fh, mnt_id, flags);
53 }
54
55 static inline int open_by_handle(int mountfd, const char *fh, int flags)
56 {
57 return open_by_handle_at(mountfd, (struct file_handle *)fh, flags);
58 }
59
60 static int handle_update_file_cred(int dirfd, const char *name, FsCred *credp)
61 {
62 int fd, ret;
63 fd = openat(dirfd, name, O_NONBLOCK | O_NOFOLLOW);
64 if (fd < 0) {
65 return fd;
66 }
67 ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
68 if (ret < 0) {
69 goto err_out;
70 }
71 ret = fchmod(fd, credp->fc_mode & 07777);
72 err_out:
73 close(fd);
74 return ret;
75 }
76
77
78 static int handle_lstat(FsContext *fs_ctx, V9fsPath *fs_path,
79 struct stat *stbuf)
80 {
81 int fd, ret;
82 struct handle_data *data = (struct handle_data *)fs_ctx->private;
83
84 fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
85 if (fd < 0) {
86 return fd;
87 }
88 ret = fstatat(fd, "", stbuf, AT_EMPTY_PATH);
89 close(fd);
90 return ret;
91 }
92
93 static ssize_t handle_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
94 char *buf, size_t bufsz)
95 {
96 int fd, ret;
97 struct handle_data *data = (struct handle_data *)fs_ctx->private;
98
99 fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
100 if (fd < 0) {
101 return fd;
102 }
103 ret = readlinkat(fd, "", buf, bufsz);
104 close(fd);
105 return ret;
106 }
107
108 static int handle_close(FsContext *ctx, V9fsFidOpenState *fs)
109 {
110 return close(fs->fd);
111 }
112
113 static int handle_closedir(FsContext *ctx, V9fsFidOpenState *fs)
114 {
115 return closedir(fs->dir.stream);
116 }
117
118 static int handle_open(FsContext *ctx, V9fsPath *fs_path,
119 int flags, V9fsFidOpenState *fs)
120 {
121 struct handle_data *data = (struct handle_data *)ctx->private;
122
123 fs->fd = open_by_handle(data->mountfd, fs_path->data, flags);
124 return fs->fd;
125 }
126
127 static int handle_opendir(FsContext *ctx,
128 V9fsPath *fs_path, V9fsFidOpenState *fs)
129 {
130 int ret;
131 ret = handle_open(ctx, fs_path, O_DIRECTORY, fs);
132 if (ret < 0) {
133 return -1;
134 }
135 fs->dir.stream = fdopendir(ret);
136 if (!fs->dir.stream) {
137 return -1;
138 }
139 return 0;
140 }
141
142 static void handle_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
143 {
144 rewinddir(fs->dir.stream);
145 }
146
147 static off_t handle_telldir(FsContext *ctx, V9fsFidOpenState *fs)
148 {
149 return telldir(fs->dir.stream);
150 }
151
152 static struct dirent *handle_readdir(FsContext *ctx, V9fsFidOpenState *fs)
153 {
154 return readdir(fs->dir.stream);
155 }
156
157 static void handle_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
158 {
159 seekdir(fs->dir.stream, off);
160 }
161
162 static ssize_t handle_preadv(FsContext *ctx, V9fsFidOpenState *fs,
163 const struct iovec *iov,
164 int iovcnt, off_t offset)
165 {
166 #ifdef CONFIG_PREADV
167 return preadv(fs->fd, iov, iovcnt, offset);
168 #else
169 int err = lseek(fs->fd, offset, SEEK_SET);
170 if (err == -1) {
171 return err;
172 } else {
173 return readv(fs->fd, iov, iovcnt);
174 }
175 #endif
176 }
177
178 static ssize_t handle_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
179 const struct iovec *iov,
180 int iovcnt, off_t offset)
181 {
182 ssize_t ret;
183 #ifdef CONFIG_PREADV
184 ret = pwritev(fs->fd, iov, iovcnt, offset);
185 #else
186 int err = lseek(fs->fd, offset, SEEK_SET);
187 if (err == -1) {
188 return err;
189 } else {
190 ret = writev(fs->fd, iov, iovcnt);
191 }
192 #endif
193 #ifdef CONFIG_SYNC_FILE_RANGE
194 if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
195 /*
196 * Initiate a writeback. This is not a data integrity sync.
197 * We want to ensure that we don't leave dirty pages in the cache
198 * after write when writeout=immediate is sepcified.
199 */
200 sync_file_range(fs->fd, offset, ret,
201 SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
202 }
203 #endif
204 return ret;
205 }
206
207 static int handle_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
208 {
209 int fd, ret;
210 struct handle_data *data = (struct handle_data *)fs_ctx->private;
211
212 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
213 if (fd < 0) {
214 return fd;
215 }
216 ret = fchmod(fd, credp->fc_mode);
217 close(fd);
218 return ret;
219 }
220
221 static int handle_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
222 const char *name, FsCred *credp)
223 {
224 int dirfd, ret;
225 struct handle_data *data = (struct handle_data *)fs_ctx->private;
226
227 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
228 if (dirfd < 0) {
229 return dirfd;
230 }
231 ret = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
232 if (!ret) {
233 ret = handle_update_file_cred(dirfd, name, credp);
234 }
235 close(dirfd);
236 return ret;
237 }
238
239 static int handle_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
240 const char *name, FsCred *credp)
241 {
242 int dirfd, ret;
243 struct handle_data *data = (struct handle_data *)fs_ctx->private;
244
245 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
246 if (dirfd < 0) {
247 return dirfd;
248 }
249 ret = mkdirat(dirfd, name, credp->fc_mode);
250 if (!ret) {
251 ret = handle_update_file_cred(dirfd, name, credp);
252 }
253 close(dirfd);
254 return ret;
255 }
256
257 static int handle_fstat(FsContext *fs_ctx, int fid_type,
258 V9fsFidOpenState *fs, struct stat *stbuf)
259 {
260 int fd;
261
262 if (fid_type == P9_FID_DIR) {
263 fd = dirfd(fs->dir.stream);
264 } else {
265 fd = fs->fd;
266 }
267 return fstat(fd, stbuf);
268 }
269
270 static int handle_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
271 int flags, FsCred *credp, V9fsFidOpenState *fs)
272 {
273 int ret;
274 int dirfd, fd;
275 struct handle_data *data = (struct handle_data *)fs_ctx->private;
276
277 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
278 if (dirfd < 0) {
279 return dirfd;
280 }
281 fd = openat(dirfd, name, flags | O_NOFOLLOW, credp->fc_mode);
282 if (fd >= 0) {
283 ret = handle_update_file_cred(dirfd, name, credp);
284 if (ret < 0) {
285 close(fd);
286 fd = ret;
287 } else {
288 fs->fd = fd;
289 }
290 }
291 close(dirfd);
292 return fd;
293 }
294
295
296 static int handle_symlink(FsContext *fs_ctx, const char *oldpath,
297 V9fsPath *dir_path, const char *name, FsCred *credp)
298 {
299 int fd, dirfd, ret;
300 struct handle_data *data = (struct handle_data *)fs_ctx->private;
301
302 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
303 if (dirfd < 0) {
304 return dirfd;
305 }
306 ret = symlinkat(oldpath, dirfd, name);
307 if (!ret) {
308 fd = openat(dirfd, name, O_PATH | O_NOFOLLOW);
309 if (fd < 0) {
310 ret = fd;
311 goto err_out;
312 }
313 ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
314 close(fd);
315 }
316 err_out:
317 close(dirfd);
318 return ret;
319 }
320
321 static int handle_link(FsContext *ctx, V9fsPath *oldpath,
322 V9fsPath *dirpath, const char *name)
323 {
324 int oldfd, newdirfd, ret;
325 struct handle_data *data = (struct handle_data *)ctx->private;
326
327 oldfd = open_by_handle(data->mountfd, oldpath->data, O_PATH);
328 if (oldfd < 0) {
329 return oldfd;
330 }
331 newdirfd = open_by_handle(data->mountfd, dirpath->data, O_PATH);
332 if (newdirfd < 0) {
333 close(oldfd);
334 return newdirfd;
335 }
336 ret = linkat(oldfd, "", newdirfd, name, AT_EMPTY_PATH);
337 close(newdirfd);
338 close(oldfd);
339 return ret;
340 }
341
342 static int handle_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
343 {
344 int fd, ret;
345 struct handle_data *data = (struct handle_data *)ctx->private;
346
347 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK | O_WRONLY);
348 if (fd < 0) {
349 return fd;
350 }
351 ret = ftruncate(fd, size);
352 close(fd);
353 return ret;
354 }
355
356 static int handle_rename(FsContext *ctx, const char *oldpath,
357 const char *newpath)
358 {
359 errno = EOPNOTSUPP;
360 return -1;
361 }
362
363 static int handle_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
364 {
365 int fd, ret;
366 struct handle_data *data = (struct handle_data *)fs_ctx->private;
367
368 fd = open_by_handle(data->mountfd, fs_path->data, O_PATH);
369 if (fd < 0) {
370 return fd;
371 }
372 ret = fchownat(fd, "", credp->fc_uid, credp->fc_gid, AT_EMPTY_PATH);
373 close(fd);
374 return ret;
375 }
376
377 static int handle_utimensat(FsContext *ctx, V9fsPath *fs_path,
378 const struct timespec *buf)
379 {
380 int ret;
381 #ifdef CONFIG_UTIMENSAT
382 int fd;
383 struct handle_data *data = (struct handle_data *)ctx->private;
384
385 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
386 if (fd < 0) {
387 return fd;
388 }
389 ret = futimens(fd, buf);
390 close(fd);
391 #else
392 ret = -1;
393 errno = ENOSYS;
394 #endif
395 return ret;
396 }
397
398 static int handle_remove(FsContext *ctx, const char *path)
399 {
400 errno = EOPNOTSUPP;
401 return -1;
402 }
403
404 static int handle_fsync(FsContext *ctx, int fid_type,
405 V9fsFidOpenState *fs, int datasync)
406 {
407 int fd;
408
409 if (fid_type == P9_FID_DIR) {
410 fd = dirfd(fs->dir.stream);
411 } else {
412 fd = fs->fd;
413 }
414
415 if (datasync) {
416 return qemu_fdatasync(fd);
417 } else {
418 return fsync(fd);
419 }
420 }
421
422 static int handle_statfs(FsContext *ctx, V9fsPath *fs_path,
423 struct statfs *stbuf)
424 {
425 int fd, ret;
426 struct handle_data *data = (struct handle_data *)ctx->private;
427
428 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
429 if (fd < 0) {
430 return fd;
431 }
432 ret = fstatfs(fd, stbuf);
433 close(fd);
434 return ret;
435 }
436
437 static ssize_t handle_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
438 const char *name, void *value, size_t size)
439 {
440 int fd, ret;
441 struct handle_data *data = (struct handle_data *)ctx->private;
442
443 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
444 if (fd < 0) {
445 return fd;
446 }
447 ret = fgetxattr(fd, name, value, size);
448 close(fd);
449 return ret;
450 }
451
452 static ssize_t handle_llistxattr(FsContext *ctx, V9fsPath *fs_path,
453 void *value, size_t size)
454 {
455 int fd, ret;
456 struct handle_data *data = (struct handle_data *)ctx->private;
457
458 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
459 if (fd < 0) {
460 return fd;
461 }
462 ret = flistxattr(fd, value, size);
463 close(fd);
464 return ret;
465 }
466
467 static int handle_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
468 void *value, size_t size, int flags)
469 {
470 int fd, ret;
471 struct handle_data *data = (struct handle_data *)ctx->private;
472
473 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
474 if (fd < 0) {
475 return fd;
476 }
477 ret = fsetxattr(fd, name, value, size, flags);
478 close(fd);
479 return ret;
480 }
481
482 static int handle_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
483 const char *name)
484 {
485 int fd, ret;
486 struct handle_data *data = (struct handle_data *)ctx->private;
487
488 fd = open_by_handle(data->mountfd, fs_path->data, O_NONBLOCK);
489 if (fd < 0) {
490 return fd;
491 }
492 ret = fremovexattr(fd, name);
493 close(fd);
494 return ret;
495 }
496
497 static int handle_name_to_path(FsContext *ctx, V9fsPath *dir_path,
498 const char *name, V9fsPath *target)
499 {
500 char *buffer;
501 struct file_handle *fh;
502 int dirfd, ret, mnt_id;
503 struct handle_data *data = (struct handle_data *)ctx->private;
504
505 /* "." and ".." are not allowed */
506 if (!strcmp(name, ".") || !strcmp(name, "..")) {
507 errno = EINVAL;
508 return -1;
509
510 }
511 if (dir_path) {
512 dirfd = open_by_handle(data->mountfd, dir_path->data, O_PATH);
513 } else {
514 /* relative to export root */
515 buffer = rpath(ctx, ".");
516 dirfd = open(buffer, O_DIRECTORY);
517 g_free(buffer);
518 }
519 if (dirfd < 0) {
520 return dirfd;
521 }
522 fh = g_malloc(sizeof(struct file_handle) + data->handle_bytes);
523 fh->handle_bytes = data->handle_bytes;
524 /* add a "./" at the beginning of the path */
525 buffer = g_strdup_printf("./%s", name);
526 /* flag = 0 imply don't follow symlink */
527 ret = name_to_handle(dirfd, buffer, fh, &mnt_id, 0);
528 if (!ret) {
529 target->data = (char *)fh;
530 target->size = sizeof(struct file_handle) + data->handle_bytes;
531 } else {
532 g_free(fh);
533 }
534 close(dirfd);
535 g_free(buffer);
536 return ret;
537 }
538
539 static int handle_renameat(FsContext *ctx, V9fsPath *olddir,
540 const char *old_name, V9fsPath *newdir,
541 const char *new_name)
542 {
543 int olddirfd, newdirfd, ret;
544 struct handle_data *data = (struct handle_data *)ctx->private;
545
546 olddirfd = open_by_handle(data->mountfd, olddir->data, O_PATH);
547 if (olddirfd < 0) {
548 return olddirfd;
549 }
550 newdirfd = open_by_handle(data->mountfd, newdir->data, O_PATH);
551 if (newdirfd < 0) {
552 close(olddirfd);
553 return newdirfd;
554 }
555 ret = renameat(olddirfd, old_name, newdirfd, new_name);
556 close(newdirfd);
557 close(olddirfd);
558 return ret;
559 }
560
561 static int handle_unlinkat(FsContext *ctx, V9fsPath *dir,
562 const char *name, int flags)
563 {
564 int dirfd, ret;
565 struct handle_data *data = (struct handle_data *)ctx->private;
566 int rflags;
567
568 dirfd = open_by_handle(data->mountfd, dir->data, O_PATH);
569 if (dirfd < 0) {
570 return dirfd;
571 }
572
573 rflags = 0;
574 if (flags & P9_DOTL_AT_REMOVEDIR) {
575 rflags |= AT_REMOVEDIR;
576 }
577
578 ret = unlinkat(dirfd, name, rflags);
579
580 close(dirfd);
581 return ret;
582 }
583
584 static int handle_ioc_getversion(FsContext *ctx, V9fsPath *path,
585 mode_t st_mode, uint64_t *st_gen)
586 {
587 #ifdef FS_IOC_GETVERSION
588 int err;
589 V9fsFidOpenState fid_open;
590
591 /*
592 * Do not try to open special files like device nodes, fifos etc
593 * We can get fd for regular files and directories only
594 */
595 if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
596 errno = ENOTTY;
597 return -1;
598 }
599 err = handle_open(ctx, path, O_RDONLY, &fid_open);
600 if (err < 0) {
601 return err;
602 }
603 err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
604 handle_close(ctx, &fid_open);
605 return err;
606 #else
607 errno = ENOTTY;
608 return -1;
609 #endif
610 }
611
612 static int handle_init(FsContext *ctx)
613 {
614 int ret, mnt_id;
615 struct statfs stbuf;
616 struct file_handle fh;
617 struct handle_data *data = g_malloc(sizeof(struct handle_data));
618
619 data->mountfd = open(ctx->fs_root, O_DIRECTORY);
620 if (data->mountfd < 0) {
621 ret = data->mountfd;
622 goto err_out;
623 }
624 ret = statfs(ctx->fs_root, &stbuf);
625 if (!ret) {
626 switch (stbuf.f_type) {
627 case EXT2_SUPER_MAGIC:
628 case BTRFS_SUPER_MAGIC:
629 case REISERFS_SUPER_MAGIC:
630 case XFS_SUPER_MAGIC:
631 ctx->exops.get_st_gen = handle_ioc_getversion;
632 break;
633 }
634 }
635 memset(&fh, 0, sizeof(struct file_handle));
636 ret = name_to_handle(data->mountfd, ".", &fh, &mnt_id, 0);
637 if (ret && errno == EOVERFLOW) {
638 data->handle_bytes = fh.handle_bytes;
639 ctx->private = data;
640 ret = 0;
641 goto out;
642 }
643 /* we got 0 byte handle ? */
644 ret = -1;
645 close(data->mountfd);
646 err_out:
647 g_free(data);
648 out:
649 return ret;
650 }
651
652 static void handle_cleanup(FsContext *ctx)
653 {
654 struct handle_data *data = ctx->private;
655
656 close(data->mountfd);
657 g_free(data);
658 }
659
660 static int handle_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
661 {
662 const char *sec_model = qemu_opt_get(opts, "security_model");
663 const char *path = qemu_opt_get(opts, "path");
664
665 if (sec_model) {
666 error_report("Invalid argument security_model specified with handle fsdriver");
667 return -1;
668 }
669
670 if (!path) {
671 error_report("fsdev: No path specified");
672 return -1;
673 }
674 fse->path = g_strdup(path);
675 return 0;
676
677 }
678
679 FileOperations handle_ops = {
680 .parse_opts = handle_parse_opts,
681 .init = handle_init,
682 .cleanup = handle_cleanup,
683 .lstat = handle_lstat,
684 .readlink = handle_readlink,
685 .close = handle_close,
686 .closedir = handle_closedir,
687 .open = handle_open,
688 .opendir = handle_opendir,
689 .rewinddir = handle_rewinddir,
690 .telldir = handle_telldir,
691 .readdir = handle_readdir,
692 .seekdir = handle_seekdir,
693 .preadv = handle_preadv,
694 .pwritev = handle_pwritev,
695 .chmod = handle_chmod,
696 .mknod = handle_mknod,
697 .mkdir = handle_mkdir,
698 .fstat = handle_fstat,
699 .open2 = handle_open2,
700 .symlink = handle_symlink,
701 .link = handle_link,
702 .truncate = handle_truncate,
703 .rename = handle_rename,
704 .chown = handle_chown,
705 .utimensat = handle_utimensat,
706 .remove = handle_remove,
707 .fsync = handle_fsync,
708 .statfs = handle_statfs,
709 .lgetxattr = handle_lgetxattr,
710 .llistxattr = handle_llistxattr,
711 .lsetxattr = handle_lsetxattr,
712 .lremovexattr = handle_lremovexattr,
713 .name_to_path = handle_name_to_path,
714 .renameat = handle_renameat,
715 .unlinkat = handle_unlinkat,
716 };