9pfs: local: improve error handling in link op
[qemu/ar7.git] / hw / 9pfs / 9p-local.c
blob2538bd317d7e76af0739e93efd2c776b9b2f5753
1 /*
2 * 9p Posix callback
4 * Copyright IBM, Corp. 2010
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
14 #include "qemu/osdep.h"
15 #include "9p.h"
16 #include "9p-local.h"
17 #include "9p-xattr.h"
18 #include "9p-util.h"
19 #include "fsdev/qemu-fsdev.h" /* local_ops */
20 #include <arpa/inet.h>
21 #include <pwd.h>
22 #include <grp.h>
23 #include <sys/socket.h>
24 #include <sys/un.h>
25 #include "qemu/xattr.h"
26 #include "qemu/cutils.h"
27 #include "qemu/error-report.h"
28 #include <libgen.h>
29 #include <linux/fs.h>
30 #ifdef CONFIG_LINUX_MAGIC_H
31 #include <linux/magic.h>
32 #endif
33 #include <sys/ioctl.h>
35 #ifndef XFS_SUPER_MAGIC
36 #define XFS_SUPER_MAGIC 0x58465342
37 #endif
38 #ifndef EXT2_SUPER_MAGIC
39 #define EXT2_SUPER_MAGIC 0xEF53
40 #endif
41 #ifndef REISERFS_SUPER_MAGIC
42 #define REISERFS_SUPER_MAGIC 0x52654973
43 #endif
44 #ifndef BTRFS_SUPER_MAGIC
45 #define BTRFS_SUPER_MAGIC 0x9123683E
46 #endif
48 typedef struct {
49 int mountfd;
50 } LocalData;
52 int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
53 mode_t mode)
55 LocalData *data = fs_ctx->private;
57 /* All paths are relative to the path data->mountfd points to */
58 while (*path == '/') {
59 path++;
62 return relative_openat_nofollow(data->mountfd, path, flags, mode);
65 int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
67 return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0);
70 static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd,
71 const char *npath)
73 int serrno = errno;
74 renameat(odirfd, opath, ndirfd, npath);
75 errno = serrno;
78 #define VIRTFS_META_DIR ".virtfs_metadata"
80 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
82 int dirlen;
83 const char *name = strrchr(path, '/');
84 if (name) {
85 dirlen = name - path;
86 ++name;
87 } else {
88 name = path;
89 dirlen = 0;
91 return g_strdup_printf("%s/%.*s/%s/%s", ctx->fs_root,
92 dirlen, path, VIRTFS_META_DIR, name);
95 static FILE *local_fopen(const char *path, const char *mode)
97 int fd, o_mode = 0;
98 FILE *fp;
99 int flags = O_NOFOLLOW;
101 * only supports two modes
103 if (mode[0] == 'r') {
104 flags |= O_RDONLY;
105 } else if (mode[0] == 'w') {
106 flags |= O_WRONLY | O_TRUNC | O_CREAT;
107 o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
108 } else {
109 return NULL;
111 fd = open(path, flags, o_mode);
112 if (fd == -1) {
113 return NULL;
115 fp = fdopen(fd, mode);
116 if (!fp) {
117 close(fd);
119 return fp;
122 static FILE *local_fopenat(int dirfd, const char *name, const char *mode)
124 int fd, o_mode = 0;
125 FILE *fp;
126 int flags;
128 * only supports two modes
130 if (mode[0] == 'r') {
131 flags = O_RDONLY;
132 } else if (mode[0] == 'w') {
133 flags = O_WRONLY | O_TRUNC | O_CREAT;
134 o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
135 } else {
136 return NULL;
138 fd = openat_file(dirfd, name, flags, o_mode);
139 if (fd == -1) {
140 return NULL;
142 fp = fdopen(fd, mode);
143 if (!fp) {
144 close(fd);
146 return fp;
149 #define ATTR_MAX 100
150 static void local_mapped_file_attr(int dirfd, const char *name,
151 struct stat *stbuf)
153 FILE *fp;
154 char buf[ATTR_MAX];
155 int map_dirfd;
157 map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
158 if (map_dirfd == -1) {
159 return;
162 fp = local_fopenat(map_dirfd, name, "r");
163 close_preserve_errno(map_dirfd);
164 if (!fp) {
165 return;
167 memset(buf, 0, ATTR_MAX);
168 while (fgets(buf, ATTR_MAX, fp)) {
169 if (!strncmp(buf, "virtfs.uid", 10)) {
170 stbuf->st_uid = atoi(buf+11);
171 } else if (!strncmp(buf, "virtfs.gid", 10)) {
172 stbuf->st_gid = atoi(buf+11);
173 } else if (!strncmp(buf, "virtfs.mode", 11)) {
174 stbuf->st_mode = atoi(buf+12);
175 } else if (!strncmp(buf, "virtfs.rdev", 11)) {
176 stbuf->st_rdev = atoi(buf+12);
178 memset(buf, 0, ATTR_MAX);
180 fclose(fp);
183 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
185 int err = -1;
186 char *dirpath = g_path_get_dirname(fs_path->data);
187 char *name = g_path_get_basename(fs_path->data);
188 int dirfd;
190 dirfd = local_opendir_nofollow(fs_ctx, dirpath);
191 if (dirfd == -1) {
192 goto out;
195 err = fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW);
196 if (err) {
197 goto err_out;
199 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
200 /* Actual credentials are part of extended attrs */
201 uid_t tmp_uid;
202 gid_t tmp_gid;
203 mode_t tmp_mode;
204 dev_t tmp_dev;
206 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.uid", &tmp_uid,
207 sizeof(uid_t)) > 0) {
208 stbuf->st_uid = le32_to_cpu(tmp_uid);
210 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.gid", &tmp_gid,
211 sizeof(gid_t)) > 0) {
212 stbuf->st_gid = le32_to_cpu(tmp_gid);
214 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.mode", &tmp_mode,
215 sizeof(mode_t)) > 0) {
216 stbuf->st_mode = le32_to_cpu(tmp_mode);
218 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.rdev", &tmp_dev,
219 sizeof(dev_t)) > 0) {
220 stbuf->st_rdev = le64_to_cpu(tmp_dev);
222 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
223 local_mapped_file_attr(dirfd, name, stbuf);
226 err_out:
227 close_preserve_errno(dirfd);
228 out:
229 g_free(name);
230 g_free(dirpath);
231 return err;
234 static int local_create_mapped_attr_dir(FsContext *ctx, const char *path)
236 int err;
237 char *attr_dir;
238 char *tmp_path = g_strdup(path);
240 attr_dir = g_strdup_printf("%s/%s/%s",
241 ctx->fs_root, dirname(tmp_path), VIRTFS_META_DIR);
243 err = mkdir(attr_dir, 0700);
244 if (err < 0 && errno == EEXIST) {
245 err = 0;
247 g_free(attr_dir);
248 g_free(tmp_path);
249 return err;
252 static int local_set_mapped_file_attr(FsContext *ctx,
253 const char *path, FsCred *credp)
255 FILE *fp;
256 int ret = 0;
257 char buf[ATTR_MAX];
258 char *attr_path;
259 int uid = -1, gid = -1, mode = -1, rdev = -1;
261 attr_path = local_mapped_attr_path(ctx, path);
262 fp = local_fopen(attr_path, "r");
263 if (!fp) {
264 goto create_map_file;
266 memset(buf, 0, ATTR_MAX);
267 while (fgets(buf, ATTR_MAX, fp)) {
268 if (!strncmp(buf, "virtfs.uid", 10)) {
269 uid = atoi(buf+11);
270 } else if (!strncmp(buf, "virtfs.gid", 10)) {
271 gid = atoi(buf+11);
272 } else if (!strncmp(buf, "virtfs.mode", 11)) {
273 mode = atoi(buf+12);
274 } else if (!strncmp(buf, "virtfs.rdev", 11)) {
275 rdev = atoi(buf+12);
277 memset(buf, 0, ATTR_MAX);
279 fclose(fp);
280 goto update_map_file;
282 create_map_file:
283 ret = local_create_mapped_attr_dir(ctx, path);
284 if (ret < 0) {
285 goto err_out;
288 update_map_file:
289 fp = local_fopen(attr_path, "w");
290 if (!fp) {
291 ret = -1;
292 goto err_out;
295 if (credp->fc_uid != -1) {
296 uid = credp->fc_uid;
298 if (credp->fc_gid != -1) {
299 gid = credp->fc_gid;
301 if (credp->fc_mode != -1) {
302 mode = credp->fc_mode;
304 if (credp->fc_rdev != -1) {
305 rdev = credp->fc_rdev;
309 if (uid != -1) {
310 fprintf(fp, "virtfs.uid=%d\n", uid);
312 if (gid != -1) {
313 fprintf(fp, "virtfs.gid=%d\n", gid);
315 if (mode != -1) {
316 fprintf(fp, "virtfs.mode=%d\n", mode);
318 if (rdev != -1) {
319 fprintf(fp, "virtfs.rdev=%d\n", rdev);
321 fclose(fp);
323 err_out:
324 g_free(attr_path);
325 return ret;
328 static int local_set_xattr(const char *path, FsCred *credp)
330 int err;
332 if (credp->fc_uid != -1) {
333 uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
334 err = setxattr(path, "user.virtfs.uid", &tmp_uid, sizeof(uid_t), 0);
335 if (err) {
336 return err;
339 if (credp->fc_gid != -1) {
340 uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
341 err = setxattr(path, "user.virtfs.gid", &tmp_gid, sizeof(gid_t), 0);
342 if (err) {
343 return err;
346 if (credp->fc_mode != -1) {
347 uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
348 err = setxattr(path, "user.virtfs.mode", &tmp_mode, sizeof(mode_t), 0);
349 if (err) {
350 return err;
353 if (credp->fc_rdev != -1) {
354 uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
355 err = setxattr(path, "user.virtfs.rdev", &tmp_rdev, sizeof(dev_t), 0);
356 if (err) {
357 return err;
360 return 0;
363 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
364 FsCred *credp)
366 char *buffer;
368 buffer = rpath(fs_ctx, path);
369 if (lchown(buffer, credp->fc_uid, credp->fc_gid) < 0) {
371 * If we fail to change ownership and if we are
372 * using security model none. Ignore the error
374 if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
375 goto err;
379 if (chmod(buffer, credp->fc_mode & 07777) < 0) {
380 goto err;
383 g_free(buffer);
384 return 0;
385 err:
386 g_free(buffer);
387 return -1;
390 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
391 char *buf, size_t bufsz)
393 ssize_t tsize = -1;
395 if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
396 (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
397 int fd;
399 fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0);
400 if (fd == -1) {
401 return -1;
403 do {
404 tsize = read(fd, (void *)buf, bufsz);
405 } while (tsize == -1 && errno == EINTR);
406 close_preserve_errno(fd);
407 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
408 (fs_ctx->export_flags & V9FS_SM_NONE)) {
409 char *dirpath = g_path_get_dirname(fs_path->data);
410 char *name = g_path_get_basename(fs_path->data);
411 int dirfd;
413 dirfd = local_opendir_nofollow(fs_ctx, dirpath);
414 if (dirfd == -1) {
415 goto out;
418 tsize = readlinkat(dirfd, name, buf, bufsz);
419 close_preserve_errno(dirfd);
420 out:
421 g_free(name);
422 g_free(dirpath);
424 return tsize;
427 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
429 return close(fs->fd);
432 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
434 return closedir(fs->dir.stream);
437 static int local_open(FsContext *ctx, V9fsPath *fs_path,
438 int flags, V9fsFidOpenState *fs)
440 int fd;
442 fd = local_open_nofollow(ctx, fs_path->data, flags, 0);
443 if (fd == -1) {
444 return -1;
446 fs->fd = fd;
447 return fs->fd;
450 static int local_opendir(FsContext *ctx,
451 V9fsPath *fs_path, V9fsFidOpenState *fs)
453 int dirfd;
454 DIR *stream;
456 dirfd = local_opendir_nofollow(ctx, fs_path->data);
457 if (dirfd == -1) {
458 return -1;
461 stream = fdopendir(dirfd);
462 if (!stream) {
463 return -1;
465 fs->dir.stream = stream;
466 return 0;
469 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
471 rewinddir(fs->dir.stream);
474 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
476 return telldir(fs->dir.stream);
479 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs)
481 struct dirent *entry;
483 again:
484 entry = readdir(fs->dir.stream);
485 if (!entry) {
486 return NULL;
489 if (ctx->export_flags & V9FS_SM_MAPPED) {
490 entry->d_type = DT_UNKNOWN;
491 } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
492 if (!strcmp(entry->d_name, VIRTFS_META_DIR)) {
493 /* skp the meta data directory */
494 goto again;
496 entry->d_type = DT_UNKNOWN;
499 return entry;
502 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
504 seekdir(fs->dir.stream, off);
507 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
508 const struct iovec *iov,
509 int iovcnt, off_t offset)
511 #ifdef CONFIG_PREADV
512 return preadv(fs->fd, iov, iovcnt, offset);
513 #else
514 int err = lseek(fs->fd, offset, SEEK_SET);
515 if (err == -1) {
516 return err;
517 } else {
518 return readv(fs->fd, iov, iovcnt);
520 #endif
523 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
524 const struct iovec *iov,
525 int iovcnt, off_t offset)
527 ssize_t ret;
528 #ifdef CONFIG_PREADV
529 ret = pwritev(fs->fd, iov, iovcnt, offset);
530 #else
531 int err = lseek(fs->fd, offset, SEEK_SET);
532 if (err == -1) {
533 return err;
534 } else {
535 ret = writev(fs->fd, iov, iovcnt);
537 #endif
538 #ifdef CONFIG_SYNC_FILE_RANGE
539 if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
541 * Initiate a writeback. This is not a data integrity sync.
542 * We want to ensure that we don't leave dirty pages in the cache
543 * after write when writeout=immediate is sepcified.
545 sync_file_range(fs->fd, offset, ret,
546 SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
548 #endif
549 return ret;
552 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
554 char *buffer;
555 int ret = -1;
556 char *path = fs_path->data;
558 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
559 buffer = rpath(fs_ctx, path);
560 ret = local_set_xattr(buffer, credp);
561 g_free(buffer);
562 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
563 return local_set_mapped_file_attr(fs_ctx, path, credp);
564 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
565 (fs_ctx->export_flags & V9FS_SM_NONE)) {
566 buffer = rpath(fs_ctx, path);
567 ret = chmod(buffer, credp->fc_mode);
568 g_free(buffer);
570 return ret;
573 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
574 const char *name, FsCred *credp)
576 char *path;
577 int err = -1;
578 int serrno = 0;
579 V9fsString fullname;
580 char *buffer = NULL;
582 v9fs_string_init(&fullname);
583 v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
584 path = fullname.data;
586 /* Determine the security model */
587 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
588 buffer = rpath(fs_ctx, path);
589 err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
590 if (err == -1) {
591 goto out;
593 err = local_set_xattr(buffer, credp);
594 if (err == -1) {
595 serrno = errno;
596 goto err_end;
598 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
600 buffer = rpath(fs_ctx, path);
601 err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
602 if (err == -1) {
603 goto out;
605 err = local_set_mapped_file_attr(fs_ctx, path, credp);
606 if (err == -1) {
607 serrno = errno;
608 goto err_end;
610 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
611 (fs_ctx->export_flags & V9FS_SM_NONE)) {
612 buffer = rpath(fs_ctx, path);
613 err = mknod(buffer, credp->fc_mode, credp->fc_rdev);
614 if (err == -1) {
615 goto out;
617 err = local_post_create_passthrough(fs_ctx, path, credp);
618 if (err == -1) {
619 serrno = errno;
620 goto err_end;
623 goto out;
625 err_end:
626 remove(buffer);
627 errno = serrno;
628 out:
629 g_free(buffer);
630 v9fs_string_free(&fullname);
631 return err;
634 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
635 const char *name, FsCred *credp)
637 char *path;
638 int err = -1;
639 int serrno = 0;
640 V9fsString fullname;
641 char *buffer = NULL;
643 v9fs_string_init(&fullname);
644 v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
645 path = fullname.data;
647 /* Determine the security model */
648 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
649 buffer = rpath(fs_ctx, path);
650 err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
651 if (err == -1) {
652 goto out;
654 credp->fc_mode = credp->fc_mode|S_IFDIR;
655 err = local_set_xattr(buffer, credp);
656 if (err == -1) {
657 serrno = errno;
658 goto err_end;
660 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
661 buffer = rpath(fs_ctx, path);
662 err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
663 if (err == -1) {
664 goto out;
666 credp->fc_mode = credp->fc_mode|S_IFDIR;
667 err = local_set_mapped_file_attr(fs_ctx, path, credp);
668 if (err == -1) {
669 serrno = errno;
670 goto err_end;
672 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
673 (fs_ctx->export_flags & V9FS_SM_NONE)) {
674 buffer = rpath(fs_ctx, path);
675 err = mkdir(buffer, credp->fc_mode);
676 if (err == -1) {
677 goto out;
679 err = local_post_create_passthrough(fs_ctx, path, credp);
680 if (err == -1) {
681 serrno = errno;
682 goto err_end;
685 goto out;
687 err_end:
688 remove(buffer);
689 errno = serrno;
690 out:
691 g_free(buffer);
692 v9fs_string_free(&fullname);
693 return err;
696 static int local_fstat(FsContext *fs_ctx, int fid_type,
697 V9fsFidOpenState *fs, struct stat *stbuf)
699 int err, fd;
701 if (fid_type == P9_FID_DIR) {
702 fd = dirfd(fs->dir.stream);
703 } else {
704 fd = fs->fd;
707 err = fstat(fd, stbuf);
708 if (err) {
709 return err;
711 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
712 /* Actual credentials are part of extended attrs */
713 uid_t tmp_uid;
714 gid_t tmp_gid;
715 mode_t tmp_mode;
716 dev_t tmp_dev;
718 if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
719 stbuf->st_uid = le32_to_cpu(tmp_uid);
721 if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
722 stbuf->st_gid = le32_to_cpu(tmp_gid);
724 if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
725 stbuf->st_mode = le32_to_cpu(tmp_mode);
727 if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
728 stbuf->st_rdev = le64_to_cpu(tmp_dev);
730 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
731 errno = EOPNOTSUPP;
732 return -1;
734 return err;
737 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
738 int flags, FsCred *credp, V9fsFidOpenState *fs)
740 char *path;
741 int fd = -1;
742 int err = -1;
743 int serrno = 0;
744 V9fsString fullname;
745 char *buffer = NULL;
748 * Mark all the open to not follow symlinks
750 flags |= O_NOFOLLOW;
752 v9fs_string_init(&fullname);
753 v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
754 path = fullname.data;
756 /* Determine the security model */
757 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
758 buffer = rpath(fs_ctx, path);
759 fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
760 if (fd == -1) {
761 err = fd;
762 goto out;
764 credp->fc_mode = credp->fc_mode|S_IFREG;
765 /* Set cleint credentials in xattr */
766 err = local_set_xattr(buffer, credp);
767 if (err == -1) {
768 serrno = errno;
769 goto err_end;
771 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
772 buffer = rpath(fs_ctx, path);
773 fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
774 if (fd == -1) {
775 err = fd;
776 goto out;
778 credp->fc_mode = credp->fc_mode|S_IFREG;
779 /* Set client credentials in .virtfs_metadata directory files */
780 err = local_set_mapped_file_attr(fs_ctx, path, credp);
781 if (err == -1) {
782 serrno = errno;
783 goto err_end;
785 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
786 (fs_ctx->export_flags & V9FS_SM_NONE)) {
787 buffer = rpath(fs_ctx, path);
788 fd = open(buffer, flags, credp->fc_mode);
789 if (fd == -1) {
790 err = fd;
791 goto out;
793 err = local_post_create_passthrough(fs_ctx, path, credp);
794 if (err == -1) {
795 serrno = errno;
796 goto err_end;
799 err = fd;
800 fs->fd = fd;
801 goto out;
803 err_end:
804 close(fd);
805 remove(buffer);
806 errno = serrno;
807 out:
808 g_free(buffer);
809 v9fs_string_free(&fullname);
810 return err;
814 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
815 V9fsPath *dir_path, const char *name, FsCred *credp)
817 int err = -1;
818 int serrno = 0;
819 char *newpath;
820 V9fsString fullname;
821 char *buffer = NULL;
823 v9fs_string_init(&fullname);
824 v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
825 newpath = fullname.data;
827 /* Determine the security model */
828 if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
829 int fd;
830 ssize_t oldpath_size, write_size;
831 buffer = rpath(fs_ctx, newpath);
832 fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
833 if (fd == -1) {
834 err = fd;
835 goto out;
837 /* Write the oldpath (target) to the file. */
838 oldpath_size = strlen(oldpath);
839 do {
840 write_size = write(fd, (void *)oldpath, oldpath_size);
841 } while (write_size == -1 && errno == EINTR);
843 if (write_size != oldpath_size) {
844 serrno = errno;
845 close(fd);
846 err = -1;
847 goto err_end;
849 close(fd);
850 /* Set cleint credentials in symlink's xattr */
851 credp->fc_mode = credp->fc_mode|S_IFLNK;
852 err = local_set_xattr(buffer, credp);
853 if (err == -1) {
854 serrno = errno;
855 goto err_end;
857 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
858 int fd;
859 ssize_t oldpath_size, write_size;
860 buffer = rpath(fs_ctx, newpath);
861 fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
862 if (fd == -1) {
863 err = fd;
864 goto out;
866 /* Write the oldpath (target) to the file. */
867 oldpath_size = strlen(oldpath);
868 do {
869 write_size = write(fd, (void *)oldpath, oldpath_size);
870 } while (write_size == -1 && errno == EINTR);
872 if (write_size != oldpath_size) {
873 serrno = errno;
874 close(fd);
875 err = -1;
876 goto err_end;
878 close(fd);
879 /* Set cleint credentials in symlink's xattr */
880 credp->fc_mode = credp->fc_mode|S_IFLNK;
881 err = local_set_mapped_file_attr(fs_ctx, newpath, credp);
882 if (err == -1) {
883 serrno = errno;
884 goto err_end;
886 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
887 (fs_ctx->export_flags & V9FS_SM_NONE)) {
888 buffer = rpath(fs_ctx, newpath);
889 err = symlink(oldpath, buffer);
890 if (err) {
891 goto out;
893 err = lchown(buffer, credp->fc_uid, credp->fc_gid);
894 if (err == -1) {
896 * If we fail to change ownership and if we are
897 * using security model none. Ignore the error
899 if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
900 serrno = errno;
901 goto err_end;
902 } else
903 err = 0;
906 goto out;
908 err_end:
909 remove(buffer);
910 errno = serrno;
911 out:
912 g_free(buffer);
913 v9fs_string_free(&fullname);
914 return err;
917 static int local_link(FsContext *ctx, V9fsPath *oldpath,
918 V9fsPath *dirpath, const char *name)
920 int ret;
921 V9fsString newpath;
922 char *buffer, *buffer1;
923 int serrno;
925 v9fs_string_init(&newpath);
926 v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
928 buffer = rpath(ctx, oldpath->data);
929 buffer1 = rpath(ctx, newpath.data);
930 ret = link(buffer, buffer1);
931 g_free(buffer);
932 if (ret < 0) {
933 goto out;
936 /* now link the virtfs_metadata files */
937 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
938 char *vbuffer, *vbuffer1;
940 /* Link the .virtfs_metadata files. Create the metada directory */
941 ret = local_create_mapped_attr_dir(ctx, newpath.data);
942 if (ret < 0) {
943 goto err_out;
945 vbuffer = local_mapped_attr_path(ctx, oldpath->data);
946 vbuffer1 = local_mapped_attr_path(ctx, newpath.data);
947 ret = link(vbuffer, vbuffer1);
948 g_free(vbuffer);
949 g_free(vbuffer1);
950 if (ret < 0 && errno != ENOENT) {
951 goto err_out;
954 goto out;
956 err_out:
957 serrno = errno;
958 remove(buffer1);
959 errno = serrno;
960 out:
961 g_free(buffer1);
962 v9fs_string_free(&newpath);
963 return ret;
966 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
968 int fd, ret;
970 fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0);
971 if (fd == -1) {
972 return -1;
974 ret = ftruncate(fd, size);
975 close_preserve_errno(fd);
976 return ret;
979 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
981 char *buffer;
982 int ret = -1;
983 char *path = fs_path->data;
985 if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
986 (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
987 (fs_ctx->export_flags & V9FS_SM_NONE)) {
988 buffer = rpath(fs_ctx, path);
989 ret = lchown(buffer, credp->fc_uid, credp->fc_gid);
990 g_free(buffer);
991 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
992 buffer = rpath(fs_ctx, path);
993 ret = local_set_xattr(buffer, credp);
994 g_free(buffer);
995 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
996 return local_set_mapped_file_attr(fs_ctx, path, credp);
998 return ret;
1001 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
1002 const struct timespec *buf)
1004 char *dirpath = g_path_get_dirname(fs_path->data);
1005 char *name = g_path_get_basename(fs_path->data);
1006 int dirfd, ret = -1;
1008 dirfd = local_opendir_nofollow(s, dirpath);
1009 if (dirfd == -1) {
1010 goto out;
1013 ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW);
1014 close_preserve_errno(dirfd);
1015 out:
1016 g_free(dirpath);
1017 g_free(name);
1018 return ret;
1021 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
1022 int flags)
1024 int ret = -1;
1026 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1027 int map_dirfd;
1029 if (flags == AT_REMOVEDIR) {
1030 int fd;
1032 fd = openat(dirfd, name, O_RDONLY | O_DIRECTORY | O_PATH);
1033 if (fd == -1) {
1034 goto err_out;
1037 * If directory remove .virtfs_metadata contained in the
1038 * directory
1040 ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
1041 close_preserve_errno(fd);
1042 if (ret < 0 && errno != ENOENT) {
1044 * We didn't had the .virtfs_metadata file. May be file created
1045 * in non-mapped mode ?. Ignore ENOENT.
1047 goto err_out;
1051 * Now remove the name from parent directory
1052 * .virtfs_metadata directory.
1054 map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
1055 ret = unlinkat(map_dirfd, name, 0);
1056 close_preserve_errno(map_dirfd);
1057 if (ret < 0 && errno != ENOENT) {
1059 * We didn't had the .virtfs_metadata file. May be file created
1060 * in non-mapped mode ?. Ignore ENOENT.
1062 goto err_out;
1066 ret = unlinkat(dirfd, name, flags);
1067 err_out:
1068 return ret;
1071 static int local_remove(FsContext *ctx, const char *path)
1073 struct stat stbuf;
1074 char *dirpath = g_path_get_dirname(path);
1075 char *name = g_path_get_basename(path);
1076 int flags = 0;
1077 int dirfd;
1078 int err = -1;
1080 dirfd = local_opendir_nofollow(ctx, dirpath);
1081 if (dirfd) {
1082 goto out;
1085 if (fstatat(dirfd, path, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) {
1086 goto err_out;
1089 if (S_ISDIR(stbuf.st_mode)) {
1090 flags |= AT_REMOVEDIR;
1093 err = local_unlinkat_common(ctx, dirfd, name, flags);
1094 err_out:
1095 close_preserve_errno(dirfd);
1096 out:
1097 g_free(name);
1098 g_free(dirpath);
1099 return err;
1102 static int local_fsync(FsContext *ctx, int fid_type,
1103 V9fsFidOpenState *fs, int datasync)
1105 int fd;
1107 if (fid_type == P9_FID_DIR) {
1108 fd = dirfd(fs->dir.stream);
1109 } else {
1110 fd = fs->fd;
1113 if (datasync) {
1114 return qemu_fdatasync(fd);
1115 } else {
1116 return fsync(fd);
1120 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
1122 int fd, ret;
1124 fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0);
1125 ret = fstatfs(fd, stbuf);
1126 close_preserve_errno(fd);
1127 return ret;
1130 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
1131 const char *name, void *value, size_t size)
1133 char *path = fs_path->data;
1135 return v9fs_get_xattr(ctx, path, name, value, size);
1138 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
1139 void *value, size_t size)
1141 char *path = fs_path->data;
1143 return v9fs_list_xattr(ctx, path, value, size);
1146 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
1147 void *value, size_t size, int flags)
1149 char *path = fs_path->data;
1151 return v9fs_set_xattr(ctx, path, name, value, size, flags);
1154 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
1155 const char *name)
1157 char *path = fs_path->data;
1159 return v9fs_remove_xattr(ctx, path, name);
1162 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
1163 const char *name, V9fsPath *target)
1165 if (dir_path) {
1166 v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
1167 } else {
1168 v9fs_path_sprintf(target, "%s", name);
1170 return 0;
1173 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
1174 const char *old_name, V9fsPath *newdir,
1175 const char *new_name)
1177 int ret;
1178 int odirfd, ndirfd;
1180 odirfd = local_opendir_nofollow(ctx, olddir->data);
1181 if (odirfd == -1) {
1182 return -1;
1185 ndirfd = local_opendir_nofollow(ctx, newdir->data);
1186 if (ndirfd == -1) {
1187 close_preserve_errno(odirfd);
1188 return -1;
1191 ret = renameat(odirfd, old_name, ndirfd, new_name);
1192 if (ret < 0) {
1193 goto out;
1196 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1197 int omap_dirfd, nmap_dirfd;
1199 ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
1200 if (ret < 0 && errno != EEXIST) {
1201 goto err_undo_rename;
1204 omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
1205 if (omap_dirfd == -1) {
1206 goto err;
1209 nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
1210 if (nmap_dirfd == -1) {
1211 close_preserve_errno(omap_dirfd);
1212 goto err;
1215 /* rename the .virtfs_metadata files */
1216 ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name);
1217 close_preserve_errno(nmap_dirfd);
1218 close_preserve_errno(omap_dirfd);
1219 if (ret < 0 && errno != ENOENT) {
1220 goto err_undo_rename;
1223 ret = 0;
1225 goto out;
1227 err:
1228 ret = -1;
1229 err_undo_rename:
1230 renameat_preserve_errno(ndirfd, new_name, odirfd, old_name);
1231 out:
1232 close_preserve_errno(ndirfd);
1233 close_preserve_errno(odirfd);
1234 return ret;
1237 static void v9fs_path_init_dirname(V9fsPath *path, const char *str)
1239 path->data = g_path_get_dirname(str);
1240 path->size = strlen(path->data) + 1;
1243 static int local_rename(FsContext *ctx, const char *oldpath,
1244 const char *newpath)
1246 int err;
1247 char *oname = g_path_get_basename(oldpath);
1248 char *nname = g_path_get_basename(newpath);
1249 V9fsPath olddir, newdir;
1251 v9fs_path_init_dirname(&olddir, oldpath);
1252 v9fs_path_init_dirname(&newdir, newpath);
1254 err = local_renameat(ctx, &olddir, oname, &newdir, nname);
1256 v9fs_path_free(&newdir);
1257 v9fs_path_free(&olddir);
1258 g_free(nname);
1259 g_free(oname);
1261 return err;
1264 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
1265 const char *name, int flags)
1267 int ret;
1268 int dirfd;
1270 dirfd = local_opendir_nofollow(ctx, dir->data);
1271 if (dirfd == -1) {
1272 return -1;
1275 ret = local_unlinkat_common(ctx, dirfd, name, flags);
1276 close_preserve_errno(dirfd);
1277 return ret;
1280 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1281 mode_t st_mode, uint64_t *st_gen)
1283 #ifdef FS_IOC_GETVERSION
1284 int err;
1285 V9fsFidOpenState fid_open;
1288 * Do not try to open special files like device nodes, fifos etc
1289 * We can get fd for regular files and directories only
1291 if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1292 errno = ENOTTY;
1293 return -1;
1295 err = local_open(ctx, path, O_RDONLY, &fid_open);
1296 if (err < 0) {
1297 return err;
1299 err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1300 local_close(ctx, &fid_open);
1301 return err;
1302 #else
1303 errno = ENOTTY;
1304 return -1;
1305 #endif
1308 static int local_init(FsContext *ctx)
1310 struct statfs stbuf;
1311 LocalData *data = g_malloc(sizeof(*data));
1313 data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
1314 if (data->mountfd == -1) {
1315 goto err;
1318 #ifdef FS_IOC_GETVERSION
1320 * use ioc_getversion only if the ioctl is definied
1322 if (fstatfs(data->mountfd, &stbuf) < 0) {
1323 close_preserve_errno(data->mountfd);
1324 goto err;
1326 switch (stbuf.f_type) {
1327 case EXT2_SUPER_MAGIC:
1328 case BTRFS_SUPER_MAGIC:
1329 case REISERFS_SUPER_MAGIC:
1330 case XFS_SUPER_MAGIC:
1331 ctx->exops.get_st_gen = local_ioc_getversion;
1332 break;
1334 #endif
1336 if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1337 ctx->xops = passthrough_xattr_ops;
1338 } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1339 ctx->xops = mapped_xattr_ops;
1340 } else if (ctx->export_flags & V9FS_SM_NONE) {
1341 ctx->xops = none_xattr_ops;
1342 } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1344 * xattr operation for mapped-file and passthrough
1345 * remain same.
1347 ctx->xops = passthrough_xattr_ops;
1349 ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1351 ctx->private = data;
1352 return 0;
1354 err:
1355 g_free(data);
1356 return -1;
1359 static void local_cleanup(FsContext *ctx)
1361 LocalData *data = ctx->private;
1363 close(data->mountfd);
1364 g_free(data);
1367 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
1369 const char *sec_model = qemu_opt_get(opts, "security_model");
1370 const char *path = qemu_opt_get(opts, "path");
1372 if (!sec_model) {
1373 error_report("Security model not specified, local fs needs security model");
1374 error_printf("valid options are:"
1375 "\tsecurity_model=[passthrough|mapped-xattr|mapped-file|none]\n");
1376 return -1;
1379 if (!strcmp(sec_model, "passthrough")) {
1380 fse->export_flags |= V9FS_SM_PASSTHROUGH;
1381 } else if (!strcmp(sec_model, "mapped") ||
1382 !strcmp(sec_model, "mapped-xattr")) {
1383 fse->export_flags |= V9FS_SM_MAPPED;
1384 } else if (!strcmp(sec_model, "none")) {
1385 fse->export_flags |= V9FS_SM_NONE;
1386 } else if (!strcmp(sec_model, "mapped-file")) {
1387 fse->export_flags |= V9FS_SM_MAPPED_FILE;
1388 } else {
1389 error_report("Invalid security model %s specified", sec_model);
1390 error_printf("valid options are:"
1391 "\t[passthrough|mapped-xattr|mapped-file|none]\n");
1392 return -1;
1395 if (!path) {
1396 error_report("fsdev: No path specified");
1397 return -1;
1399 fse->path = g_strdup(path);
1401 return 0;
1404 FileOperations local_ops = {
1405 .parse_opts = local_parse_opts,
1406 .init = local_init,
1407 .cleanup = local_cleanup,
1408 .lstat = local_lstat,
1409 .readlink = local_readlink,
1410 .close = local_close,
1411 .closedir = local_closedir,
1412 .open = local_open,
1413 .opendir = local_opendir,
1414 .rewinddir = local_rewinddir,
1415 .telldir = local_telldir,
1416 .readdir = local_readdir,
1417 .seekdir = local_seekdir,
1418 .preadv = local_preadv,
1419 .pwritev = local_pwritev,
1420 .chmod = local_chmod,
1421 .mknod = local_mknod,
1422 .mkdir = local_mkdir,
1423 .fstat = local_fstat,
1424 .open2 = local_open2,
1425 .symlink = local_symlink,
1426 .link = local_link,
1427 .truncate = local_truncate,
1428 .rename = local_rename,
1429 .chown = local_chown,
1430 .utimensat = local_utimensat,
1431 .remove = local_remove,
1432 .fsync = local_fsync,
1433 .statfs = local_statfs,
1434 .lgetxattr = local_lgetxattr,
1435 .llistxattr = local_llistxattr,
1436 .lsetxattr = local_lsetxattr,
1437 .lremovexattr = local_lremovexattr,
1438 .name_to_path = local_name_to_path,
1439 .renameat = local_renameat,
1440 .unlinkat = local_unlinkat,