xref: /openbmc/qemu/hw/9pfs/9p-local.c (revision e4ec5ad4)
1 /*
2  * 9p Posix callback
3  *
4  * Copyright IBM, Corp. 2010
5  *
6  * Authors:
7  *  Anthony Liguori   <aliguori@us.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 #include "qemu/osdep.h"
14 #include "9p.h"
15 #include "9p-local.h"
16 #include "9p-xattr.h"
17 #include "9p-util.h"
18 #include "fsdev/qemu-fsdev.h"   /* local_ops */
19 #include <arpa/inet.h>
20 #include <pwd.h>
21 #include <grp.h>
22 #include <sys/socket.h>
23 #include <sys/un.h>
24 #include "qemu/xattr.h"
25 #include "qapi/error.h"
26 #include "qemu/cutils.h"
27 #include "qemu/error-report.h"
28 #include "qemu/option.h"
29 #include <libgen.h>
30 #include <linux/fs.h>
31 #ifdef CONFIG_LINUX_MAGIC_H
32 #include <linux/magic.h>
33 #endif
34 #include <sys/ioctl.h>
35 
36 #ifndef XFS_SUPER_MAGIC
37 #define XFS_SUPER_MAGIC  0x58465342
38 #endif
39 #ifndef EXT2_SUPER_MAGIC
40 #define EXT2_SUPER_MAGIC 0xEF53
41 #endif
42 #ifndef REISERFS_SUPER_MAGIC
43 #define REISERFS_SUPER_MAGIC 0x52654973
44 #endif
45 #ifndef BTRFS_SUPER_MAGIC
46 #define BTRFS_SUPER_MAGIC 0x9123683E
47 #endif
48 
49 typedef struct {
50     int mountfd;
51 } LocalData;
52 
53 int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
54                         mode_t mode)
55 {
56     LocalData *data = fs_ctx->private;
57     int fd = data->mountfd;
58 
59     while (*path && fd != -1) {
60         const char *c;
61         int next_fd;
62         char *head;
63 
64         /* Only relative paths without consecutive slashes */
65         assert(*path != '/');
66 
67         head = g_strdup(path);
68         c = qemu_strchrnul(path, '/');
69         if (*c) {
70             /* Intermediate path element */
71             head[c - path] = 0;
72             path = c + 1;
73             next_fd = openat_dir(fd, head);
74         } else {
75             /* Rightmost path element */
76             next_fd = openat_file(fd, head, flags, mode);
77             path = c;
78         }
79         g_free(head);
80         if (fd != data->mountfd) {
81             close_preserve_errno(fd);
82         }
83         fd = next_fd;
84     }
85 
86     assert(fd != data->mountfd);
87     return fd;
88 }
89 
90 int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
91 {
92     return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0);
93 }
94 
95 static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd,
96                                     const char *npath)
97 {
98     int serrno = errno;
99     renameat(odirfd, opath, ndirfd, npath);
100     errno = serrno;
101 }
102 
103 static void unlinkat_preserve_errno(int dirfd, const char *path, int flags)
104 {
105     int serrno = errno;
106     unlinkat(dirfd, path, flags);
107     errno = serrno;
108 }
109 
110 #define VIRTFS_META_DIR ".virtfs_metadata"
111 #define VIRTFS_META_ROOT_FILE VIRTFS_META_DIR "_root"
112 
113 static FILE *local_fopenat(int dirfd, const char *name, const char *mode)
114 {
115     int fd, o_mode = 0;
116     FILE *fp;
117     int flags;
118     /*
119      * only supports two modes
120      */
121     if (mode[0] == 'r') {
122         flags = O_RDONLY;
123     } else if (mode[0] == 'w') {
124         flags = O_WRONLY | O_TRUNC | O_CREAT;
125         o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
126     } else {
127         return NULL;
128     }
129     fd = openat_file(dirfd, name, flags, o_mode);
130     if (fd == -1) {
131         return NULL;
132     }
133     fp = fdopen(fd, mode);
134     if (!fp) {
135         close(fd);
136     }
137     return fp;
138 }
139 
140 #define ATTR_MAX 100
141 static void local_mapped_file_attr(int dirfd, const char *name,
142                                    struct stat *stbuf)
143 {
144     FILE *fp;
145     char buf[ATTR_MAX];
146     int map_dirfd;
147 
148     if (strcmp(name, ".")) {
149         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
150         if (map_dirfd == -1) {
151             return;
152         }
153 
154         fp = local_fopenat(map_dirfd, name, "r");
155         close_preserve_errno(map_dirfd);
156     } else {
157         fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "r");
158     }
159     if (!fp) {
160         return;
161     }
162     memset(buf, 0, ATTR_MAX);
163     while (fgets(buf, ATTR_MAX, fp)) {
164         if (!strncmp(buf, "virtfs.uid", 10)) {
165             stbuf->st_uid = atoi(buf+11);
166         } else if (!strncmp(buf, "virtfs.gid", 10)) {
167             stbuf->st_gid = atoi(buf+11);
168         } else if (!strncmp(buf, "virtfs.mode", 11)) {
169             stbuf->st_mode = atoi(buf+12);
170         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
171             stbuf->st_rdev = atoi(buf+12);
172         }
173         memset(buf, 0, ATTR_MAX);
174     }
175     fclose(fp);
176 }
177 
178 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
179 {
180     int err = -1;
181     char *dirpath = g_path_get_dirname(fs_path->data);
182     char *name = g_path_get_basename(fs_path->data);
183     int dirfd;
184 
185     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
186     if (dirfd == -1) {
187         goto out;
188     }
189 
190     err = fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW);
191     if (err) {
192         goto err_out;
193     }
194     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
195         /* Actual credentials are part of extended attrs */
196         uid_t tmp_uid;
197         gid_t tmp_gid;
198         mode_t tmp_mode;
199         dev_t tmp_dev;
200 
201         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.uid", &tmp_uid,
202                                  sizeof(uid_t)) > 0) {
203             stbuf->st_uid = le32_to_cpu(tmp_uid);
204         }
205         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.gid", &tmp_gid,
206                                  sizeof(gid_t)) > 0) {
207             stbuf->st_gid = le32_to_cpu(tmp_gid);
208         }
209         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.mode", &tmp_mode,
210                                  sizeof(mode_t)) > 0) {
211             stbuf->st_mode = le32_to_cpu(tmp_mode);
212         }
213         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.rdev", &tmp_dev,
214                                  sizeof(dev_t)) > 0) {
215             stbuf->st_rdev = le64_to_cpu(tmp_dev);
216         }
217     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
218         local_mapped_file_attr(dirfd, name, stbuf);
219     }
220 
221 err_out:
222     close_preserve_errno(dirfd);
223 out:
224     g_free(name);
225     g_free(dirpath);
226     return err;
227 }
228 
229 static int local_set_mapped_file_attrat(int dirfd, const char *name,
230                                         FsCred *credp)
231 {
232     FILE *fp;
233     int ret;
234     char buf[ATTR_MAX];
235     int uid = -1, gid = -1, mode = -1, rdev = -1;
236     int map_dirfd = -1, map_fd;
237     bool is_root = !strcmp(name, ".");
238 
239     if (is_root) {
240         fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "r");
241         if (!fp) {
242             if (errno == ENOENT) {
243                 goto update_map_file;
244             } else {
245                 return -1;
246             }
247         }
248     } else {
249         ret = mkdirat(dirfd, VIRTFS_META_DIR, 0700);
250         if (ret < 0 && errno != EEXIST) {
251             return -1;
252         }
253 
254         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
255         if (map_dirfd == -1) {
256             return -1;
257         }
258 
259         fp = local_fopenat(map_dirfd, name, "r");
260         if (!fp) {
261             if (errno == ENOENT) {
262                 goto update_map_file;
263             } else {
264                 close_preserve_errno(map_dirfd);
265                 return -1;
266             }
267         }
268     }
269     memset(buf, 0, ATTR_MAX);
270     while (fgets(buf, ATTR_MAX, fp)) {
271         if (!strncmp(buf, "virtfs.uid", 10)) {
272             uid = atoi(buf + 11);
273         } else if (!strncmp(buf, "virtfs.gid", 10)) {
274             gid = atoi(buf + 11);
275         } else if (!strncmp(buf, "virtfs.mode", 11)) {
276             mode = atoi(buf + 12);
277         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
278             rdev = atoi(buf + 12);
279         }
280         memset(buf, 0, ATTR_MAX);
281     }
282     fclose(fp);
283 
284 update_map_file:
285     if (is_root) {
286         fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "w");
287     } else {
288         fp = local_fopenat(map_dirfd, name, "w");
289         /* We can't go this far with map_dirfd not being a valid file descriptor
290          * but some versions of gcc aren't smart enough to see it.
291          */
292         if (map_dirfd != -1) {
293             close_preserve_errno(map_dirfd);
294         }
295     }
296     if (!fp) {
297         return -1;
298     }
299 
300     map_fd = fileno(fp);
301     assert(map_fd != -1);
302     ret = fchmod(map_fd, 0600);
303     assert(ret == 0);
304 
305     if (credp->fc_uid != -1) {
306         uid = credp->fc_uid;
307     }
308     if (credp->fc_gid != -1) {
309         gid = credp->fc_gid;
310     }
311     if (credp->fc_mode != (mode_t)-1) {
312         mode = credp->fc_mode;
313     }
314     if (credp->fc_rdev != -1) {
315         rdev = credp->fc_rdev;
316     }
317 
318     if (uid != -1) {
319         fprintf(fp, "virtfs.uid=%d\n", uid);
320     }
321     if (gid != -1) {
322         fprintf(fp, "virtfs.gid=%d\n", gid);
323     }
324     if (mode != -1) {
325         fprintf(fp, "virtfs.mode=%d\n", mode);
326     }
327     if (rdev != -1) {
328         fprintf(fp, "virtfs.rdev=%d\n", rdev);
329     }
330     fclose(fp);
331 
332     return 0;
333 }
334 
335 static int fchmodat_nofollow(int dirfd, const char *name, mode_t mode)
336 {
337     struct stat stbuf;
338     int fd, ret;
339 
340     /* FIXME: this should be handled with fchmodat(AT_SYMLINK_NOFOLLOW).
341      * Unfortunately, the linux kernel doesn't implement it yet.
342      */
343 
344      /* First, we clear non-racing symlinks out of the way. */
345     if (fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW)) {
346         return -1;
347     }
348     if (S_ISLNK(stbuf.st_mode)) {
349         errno = ELOOP;
350         return -1;
351     }
352 
353     fd = openat_file(dirfd, name, O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
354 #if O_PATH_9P_UTIL == 0
355     /* Fallback for systems that don't support O_PATH: we depend on the file
356      * being readable or writable.
357      */
358     if (fd == -1) {
359         /* In case the file is writable-only and isn't a directory. */
360         if (errno == EACCES) {
361             fd = openat_file(dirfd, name, O_WRONLY, 0);
362         }
363         if (fd == -1 && errno == EISDIR) {
364             errno = EACCES;
365         }
366     }
367     if (fd == -1) {
368         return -1;
369     }
370     ret = fchmod(fd, mode);
371 #else
372     /* Access modes are ignored when O_PATH is supported. If name is a symbolic
373      * link, O_PATH | O_NOFOLLOW causes openat(2) to return a file descriptor
374      * referring to the symbolic link.
375      */
376     if (fd == -1) {
377         return -1;
378     }
379 
380     /* Now we handle racing symlinks. */
381     ret = fstat(fd, &stbuf);
382     if (!ret) {
383         if (S_ISLNK(stbuf.st_mode)) {
384             errno = ELOOP;
385             ret = -1;
386         } else {
387             char *proc_path = g_strdup_printf("/proc/self/fd/%d", fd);
388             ret = chmod(proc_path, mode);
389             g_free(proc_path);
390         }
391     }
392 #endif
393     close_preserve_errno(fd);
394     return ret;
395 }
396 
397 static int local_set_xattrat(int dirfd, const char *path, FsCred *credp)
398 {
399     int err;
400 
401     if (credp->fc_uid != -1) {
402         uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
403         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.uid", &tmp_uid,
404                                    sizeof(uid_t), 0);
405         if (err) {
406             return err;
407         }
408     }
409     if (credp->fc_gid != -1) {
410         uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
411         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.gid", &tmp_gid,
412                                    sizeof(gid_t), 0);
413         if (err) {
414             return err;
415         }
416     }
417     if (credp->fc_mode != (mode_t)-1) {
418         uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
419         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.mode", &tmp_mode,
420                                    sizeof(mode_t), 0);
421         if (err) {
422             return err;
423         }
424     }
425     if (credp->fc_rdev != -1) {
426         uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
427         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.rdev", &tmp_rdev,
428                                    sizeof(dev_t), 0);
429         if (err) {
430             return err;
431         }
432     }
433     return 0;
434 }
435 
436 static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd,
437                                       const char *name, FsCred *credp)
438 {
439     if (fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
440                  AT_SYMLINK_NOFOLLOW) < 0) {
441         /*
442          * If we fail to change ownership and if we are
443          * using security model none. Ignore the error
444          */
445         if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
446             return -1;
447         }
448     }
449 
450     return fchmodat_nofollow(dirfd, name, credp->fc_mode & 07777);
451 }
452 
453 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
454                               char *buf, size_t bufsz)
455 {
456     ssize_t tsize = -1;
457 
458     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
459         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
460         int fd;
461 
462         fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0);
463         if (fd == -1) {
464             return -1;
465         }
466         do {
467             tsize = read(fd, (void *)buf, bufsz);
468         } while (tsize == -1 && errno == EINTR);
469         close_preserve_errno(fd);
470     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
471                (fs_ctx->export_flags & V9FS_SM_NONE)) {
472         char *dirpath = g_path_get_dirname(fs_path->data);
473         char *name = g_path_get_basename(fs_path->data);
474         int dirfd;
475 
476         dirfd = local_opendir_nofollow(fs_ctx, dirpath);
477         if (dirfd == -1) {
478             goto out;
479         }
480 
481         tsize = readlinkat(dirfd, name, buf, bufsz);
482         close_preserve_errno(dirfd);
483     out:
484         g_free(name);
485         g_free(dirpath);
486     }
487     return tsize;
488 }
489 
490 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
491 {
492     return close(fs->fd);
493 }
494 
495 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
496 {
497     return closedir(fs->dir.stream);
498 }
499 
500 static int local_open(FsContext *ctx, V9fsPath *fs_path,
501                       int flags, V9fsFidOpenState *fs)
502 {
503     int fd;
504 
505     fd = local_open_nofollow(ctx, fs_path->data, flags, 0);
506     if (fd == -1) {
507         return -1;
508     }
509     fs->fd = fd;
510     return fs->fd;
511 }
512 
513 static int local_opendir(FsContext *ctx,
514                          V9fsPath *fs_path, V9fsFidOpenState *fs)
515 {
516     int dirfd;
517     DIR *stream;
518 
519     dirfd = local_opendir_nofollow(ctx, fs_path->data);
520     if (dirfd == -1) {
521         return -1;
522     }
523 
524     stream = fdopendir(dirfd);
525     if (!stream) {
526         close(dirfd);
527         return -1;
528     }
529     fs->dir.stream = stream;
530     return 0;
531 }
532 
533 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
534 {
535     rewinddir(fs->dir.stream);
536 }
537 
538 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
539 {
540     return telldir(fs->dir.stream);
541 }
542 
543 static bool local_is_mapped_file_metadata(FsContext *fs_ctx, const char *name)
544 {
545     return
546         !strcmp(name, VIRTFS_META_DIR) || !strcmp(name, VIRTFS_META_ROOT_FILE);
547 }
548 
549 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs)
550 {
551     struct dirent *entry;
552 
553 again:
554     entry = readdir(fs->dir.stream);
555     if (!entry) {
556         return NULL;
557     }
558 
559     if (ctx->export_flags & V9FS_SM_MAPPED) {
560         entry->d_type = DT_UNKNOWN;
561     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
562         if (local_is_mapped_file_metadata(ctx, entry->d_name)) {
563             /* skip the meta data */
564             goto again;
565         }
566         entry->d_type = DT_UNKNOWN;
567     }
568 
569     return entry;
570 }
571 
572 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
573 {
574     seekdir(fs->dir.stream, off);
575 }
576 
577 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
578                             const struct iovec *iov,
579                             int iovcnt, off_t offset)
580 {
581 #ifdef CONFIG_PREADV
582     return preadv(fs->fd, iov, iovcnt, offset);
583 #else
584     int err = lseek(fs->fd, offset, SEEK_SET);
585     if (err == -1) {
586         return err;
587     } else {
588         return readv(fs->fd, iov, iovcnt);
589     }
590 #endif
591 }
592 
593 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
594                              const struct iovec *iov,
595                              int iovcnt, off_t offset)
596 {
597     ssize_t ret;
598 #ifdef CONFIG_PREADV
599     ret = pwritev(fs->fd, iov, iovcnt, offset);
600 #else
601     int err = lseek(fs->fd, offset, SEEK_SET);
602     if (err == -1) {
603         return err;
604     } else {
605         ret = writev(fs->fd, iov, iovcnt);
606     }
607 #endif
608 #ifdef CONFIG_SYNC_FILE_RANGE
609     if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
610         /*
611          * Initiate a writeback. This is not a data integrity sync.
612          * We want to ensure that we don't leave dirty pages in the cache
613          * after write when writeout=immediate is sepcified.
614          */
615         sync_file_range(fs->fd, offset, ret,
616                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
617     }
618 #endif
619     return ret;
620 }
621 
622 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
623 {
624     char *dirpath = g_path_get_dirname(fs_path->data);
625     char *name = g_path_get_basename(fs_path->data);
626     int ret = -1;
627     int dirfd;
628 
629     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
630     if (dirfd == -1) {
631         goto out;
632     }
633 
634     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
635         ret = local_set_xattrat(dirfd, name, credp);
636     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
637         ret = local_set_mapped_file_attrat(dirfd, name, credp);
638     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
639                fs_ctx->export_flags & V9FS_SM_NONE) {
640         ret = fchmodat_nofollow(dirfd, name, credp->fc_mode);
641     }
642     close_preserve_errno(dirfd);
643 
644 out:
645     g_free(dirpath);
646     g_free(name);
647     return ret;
648 }
649 
650 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
651                        const char *name, FsCred *credp)
652 {
653     int err = -1;
654     int dirfd;
655 
656     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
657         local_is_mapped_file_metadata(fs_ctx, name)) {
658         errno = EINVAL;
659         return -1;
660     }
661 
662     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
663     if (dirfd == -1) {
664         return -1;
665     }
666 
667     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
668         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
669         err = mknodat(dirfd, name, fs_ctx->fmode | S_IFREG, 0);
670         if (err == -1) {
671             goto out;
672         }
673 
674         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
675             err = local_set_xattrat(dirfd, name, credp);
676         } else {
677             err = local_set_mapped_file_attrat(dirfd, name, credp);
678         }
679         if (err == -1) {
680             goto err_end;
681         }
682     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
683                fs_ctx->export_flags & V9FS_SM_NONE) {
684         err = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
685         if (err == -1) {
686             goto out;
687         }
688         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
689         if (err == -1) {
690             goto err_end;
691         }
692     }
693     goto out;
694 
695 err_end:
696     unlinkat_preserve_errno(dirfd, name, 0);
697 out:
698     close_preserve_errno(dirfd);
699     return err;
700 }
701 
702 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
703                        const char *name, FsCred *credp)
704 {
705     int err = -1;
706     int dirfd;
707 
708     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
709         local_is_mapped_file_metadata(fs_ctx, name)) {
710         errno = EINVAL;
711         return -1;
712     }
713 
714     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
715     if (dirfd == -1) {
716         return -1;
717     }
718 
719     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
720         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
721         err = mkdirat(dirfd, name, fs_ctx->dmode);
722         if (err == -1) {
723             goto out;
724         }
725         credp->fc_mode = credp->fc_mode | S_IFDIR;
726 
727         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
728             err = local_set_xattrat(dirfd, name, credp);
729         } else {
730             err = local_set_mapped_file_attrat(dirfd, name, credp);
731         }
732         if (err == -1) {
733             goto err_end;
734         }
735     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
736                fs_ctx->export_flags & V9FS_SM_NONE) {
737         err = mkdirat(dirfd, name, credp->fc_mode);
738         if (err == -1) {
739             goto out;
740         }
741         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
742         if (err == -1) {
743             goto err_end;
744         }
745     }
746     goto out;
747 
748 err_end:
749     unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR);
750 out:
751     close_preserve_errno(dirfd);
752     return err;
753 }
754 
755 static int local_fstat(FsContext *fs_ctx, int fid_type,
756                        V9fsFidOpenState *fs, struct stat *stbuf)
757 {
758     int err, fd;
759 
760     if (fid_type == P9_FID_DIR) {
761         fd = dirfd(fs->dir.stream);
762     } else {
763         fd = fs->fd;
764     }
765 
766     err = fstat(fd, stbuf);
767     if (err) {
768         return err;
769     }
770     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
771         /* Actual credentials are part of extended attrs */
772         uid_t tmp_uid;
773         gid_t tmp_gid;
774         mode_t tmp_mode;
775         dev_t tmp_dev;
776 
777         if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
778             stbuf->st_uid = le32_to_cpu(tmp_uid);
779         }
780         if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
781             stbuf->st_gid = le32_to_cpu(tmp_gid);
782         }
783         if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
784             stbuf->st_mode = le32_to_cpu(tmp_mode);
785         }
786         if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
787             stbuf->st_rdev = le64_to_cpu(tmp_dev);
788         }
789     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
790         errno = EOPNOTSUPP;
791         return -1;
792     }
793     return err;
794 }
795 
796 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
797                        int flags, FsCred *credp, V9fsFidOpenState *fs)
798 {
799     int fd = -1;
800     int err = -1;
801     int dirfd;
802 
803     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
804         local_is_mapped_file_metadata(fs_ctx, name)) {
805         errno = EINVAL;
806         return -1;
807     }
808 
809     /*
810      * Mark all the open to not follow symlinks
811      */
812     flags |= O_NOFOLLOW;
813 
814     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
815     if (dirfd == -1) {
816         return -1;
817     }
818 
819     /* Determine the security model */
820     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
821         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
822         fd = openat_file(dirfd, name, flags, fs_ctx->fmode);
823         if (fd == -1) {
824             goto out;
825         }
826         credp->fc_mode = credp->fc_mode|S_IFREG;
827         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
828             /* Set cleint credentials in xattr */
829             err = local_set_xattrat(dirfd, name, credp);
830         } else {
831             err = local_set_mapped_file_attrat(dirfd, name, credp);
832         }
833         if (err == -1) {
834             goto err_end;
835         }
836     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
837                (fs_ctx->export_flags & V9FS_SM_NONE)) {
838         fd = openat_file(dirfd, name, flags, credp->fc_mode);
839         if (fd == -1) {
840             goto out;
841         }
842         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
843         if (err == -1) {
844             goto err_end;
845         }
846     }
847     err = fd;
848     fs->fd = fd;
849     goto out;
850 
851 err_end:
852     unlinkat_preserve_errno(dirfd, name,
853                             flags & O_DIRECTORY ? AT_REMOVEDIR : 0);
854     close_preserve_errno(fd);
855 out:
856     close_preserve_errno(dirfd);
857     return err;
858 }
859 
860 
861 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
862                          V9fsPath *dir_path, const char *name, FsCred *credp)
863 {
864     int err = -1;
865     int dirfd;
866 
867     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
868         local_is_mapped_file_metadata(fs_ctx, name)) {
869         errno = EINVAL;
870         return -1;
871     }
872 
873     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
874     if (dirfd == -1) {
875         return -1;
876     }
877 
878     /* Determine the security model */
879     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
880         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
881         int fd;
882         ssize_t oldpath_size, write_size;
883 
884         fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR,
885                          fs_ctx->fmode);
886         if (fd == -1) {
887             goto out;
888         }
889         /* Write the oldpath (target) to the file. */
890         oldpath_size = strlen(oldpath);
891         do {
892             write_size = write(fd, (void *)oldpath, oldpath_size);
893         } while (write_size == -1 && errno == EINTR);
894         close_preserve_errno(fd);
895 
896         if (write_size != oldpath_size) {
897             goto err_end;
898         }
899         /* Set cleint credentials in symlink's xattr */
900         credp->fc_mode = credp->fc_mode | S_IFLNK;
901 
902         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
903             err = local_set_xattrat(dirfd, name, credp);
904         } else {
905             err = local_set_mapped_file_attrat(dirfd, name, credp);
906         }
907         if (err == -1) {
908             goto err_end;
909         }
910     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
911                fs_ctx->export_flags & V9FS_SM_NONE) {
912         err = symlinkat(oldpath, dirfd, name);
913         if (err) {
914             goto out;
915         }
916         err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
917                        AT_SYMLINK_NOFOLLOW);
918         if (err == -1) {
919             /*
920              * If we fail to change ownership and if we are
921              * using security model none. Ignore the error
922              */
923             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
924                 goto err_end;
925             } else {
926                 err = 0;
927             }
928         }
929     }
930     goto out;
931 
932 err_end:
933     unlinkat_preserve_errno(dirfd, name, 0);
934 out:
935     close_preserve_errno(dirfd);
936     return err;
937 }
938 
939 static int local_link(FsContext *ctx, V9fsPath *oldpath,
940                       V9fsPath *dirpath, const char *name)
941 {
942     char *odirpath = g_path_get_dirname(oldpath->data);
943     char *oname = g_path_get_basename(oldpath->data);
944     int ret = -1;
945     int odirfd, ndirfd;
946 
947     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
948         local_is_mapped_file_metadata(ctx, name)) {
949         errno = EINVAL;
950         return -1;
951     }
952 
953     odirfd = local_opendir_nofollow(ctx, odirpath);
954     if (odirfd == -1) {
955         goto out;
956     }
957 
958     ndirfd = local_opendir_nofollow(ctx, dirpath->data);
959     if (ndirfd == -1) {
960         close_preserve_errno(odirfd);
961         goto out;
962     }
963 
964     ret = linkat(odirfd, oname, ndirfd, name, 0);
965     if (ret < 0) {
966         goto out_close;
967     }
968 
969     /* now link the virtfs_metadata files */
970     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
971         int omap_dirfd, nmap_dirfd;
972 
973         ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
974         if (ret < 0 && errno != EEXIST) {
975             goto err_undo_link;
976         }
977 
978         omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
979         if (omap_dirfd == -1) {
980             goto err;
981         }
982 
983         nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
984         if (nmap_dirfd == -1) {
985             close_preserve_errno(omap_dirfd);
986             goto err;
987         }
988 
989         ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0);
990         close_preserve_errno(nmap_dirfd);
991         close_preserve_errno(omap_dirfd);
992         if (ret < 0 && errno != ENOENT) {
993             goto err_undo_link;
994         }
995 
996         ret = 0;
997     }
998     goto out_close;
999 
1000 err:
1001     ret = -1;
1002 err_undo_link:
1003     unlinkat_preserve_errno(ndirfd, name, 0);
1004 out_close:
1005     close_preserve_errno(ndirfd);
1006     close_preserve_errno(odirfd);
1007 out:
1008     g_free(oname);
1009     g_free(odirpath);
1010     return ret;
1011 }
1012 
1013 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
1014 {
1015     int fd, ret;
1016 
1017     fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0);
1018     if (fd == -1) {
1019         return -1;
1020     }
1021     ret = ftruncate(fd, size);
1022     close_preserve_errno(fd);
1023     return ret;
1024 }
1025 
1026 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
1027 {
1028     char *dirpath = g_path_get_dirname(fs_path->data);
1029     char *name = g_path_get_basename(fs_path->data);
1030     int ret = -1;
1031     int dirfd;
1032 
1033     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
1034     if (dirfd == -1) {
1035         goto out;
1036     }
1037 
1038     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
1039         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
1040         (fs_ctx->export_flags & V9FS_SM_NONE)) {
1041         ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
1042                        AT_SYMLINK_NOFOLLOW);
1043     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
1044         ret = local_set_xattrat(dirfd, name, credp);
1045     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1046         ret = local_set_mapped_file_attrat(dirfd, name, credp);
1047     }
1048 
1049     close_preserve_errno(dirfd);
1050 out:
1051     g_free(name);
1052     g_free(dirpath);
1053     return ret;
1054 }
1055 
1056 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
1057                            const struct timespec *buf)
1058 {
1059     char *dirpath = g_path_get_dirname(fs_path->data);
1060     char *name = g_path_get_basename(fs_path->data);
1061     int dirfd, ret = -1;
1062 
1063     dirfd = local_opendir_nofollow(s, dirpath);
1064     if (dirfd == -1) {
1065         goto out;
1066     }
1067 
1068     ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW);
1069     close_preserve_errno(dirfd);
1070 out:
1071     g_free(dirpath);
1072     g_free(name);
1073     return ret;
1074 }
1075 
1076 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
1077                                  int flags)
1078 {
1079     int ret = -1;
1080 
1081     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1082         int map_dirfd;
1083 
1084         /* We need to remove the metadata as well:
1085          * - the metadata directory if we're removing a directory
1086          * - the metadata file in the parent's metadata directory
1087          *
1088          * If any of these are missing (ie, ENOENT) then we're probably
1089          * trying to remove something that wasn't created in mapped-file
1090          * mode. We just ignore the error.
1091          */
1092         if (flags == AT_REMOVEDIR) {
1093             int fd;
1094 
1095             fd = openat_dir(dirfd, name);
1096             if (fd == -1) {
1097                 goto err_out;
1098             }
1099             ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
1100             close_preserve_errno(fd);
1101             if (ret < 0 && errno != ENOENT) {
1102                 goto err_out;
1103             }
1104         }
1105         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
1106         if (map_dirfd != -1) {
1107             ret = unlinkat(map_dirfd, name, 0);
1108             close_preserve_errno(map_dirfd);
1109             if (ret < 0 && errno != ENOENT) {
1110                 goto err_out;
1111             }
1112         } else if (errno != ENOENT) {
1113             goto err_out;
1114         }
1115     }
1116 
1117     ret = unlinkat(dirfd, name, flags);
1118 err_out:
1119     return ret;
1120 }
1121 
1122 static int local_remove(FsContext *ctx, const char *path)
1123 {
1124     struct stat stbuf;
1125     char *dirpath = g_path_get_dirname(path);
1126     char *name = g_path_get_basename(path);
1127     int flags = 0;
1128     int dirfd;
1129     int err = -1;
1130 
1131     dirfd = local_opendir_nofollow(ctx, dirpath);
1132     if (dirfd == -1) {
1133         goto out;
1134     }
1135 
1136     if (fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) {
1137         goto err_out;
1138     }
1139 
1140     if (S_ISDIR(stbuf.st_mode)) {
1141         flags |= AT_REMOVEDIR;
1142     }
1143 
1144     err = local_unlinkat_common(ctx, dirfd, name, flags);
1145 err_out:
1146     close_preserve_errno(dirfd);
1147 out:
1148     g_free(name);
1149     g_free(dirpath);
1150     return err;
1151 }
1152 
1153 static int local_fsync(FsContext *ctx, int fid_type,
1154                        V9fsFidOpenState *fs, int datasync)
1155 {
1156     int fd;
1157 
1158     if (fid_type == P9_FID_DIR) {
1159         fd = dirfd(fs->dir.stream);
1160     } else {
1161         fd = fs->fd;
1162     }
1163 
1164     if (datasync) {
1165         return qemu_fdatasync(fd);
1166     } else {
1167         return fsync(fd);
1168     }
1169 }
1170 
1171 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
1172 {
1173     int fd, ret;
1174 
1175     fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0);
1176     if (fd == -1) {
1177         return -1;
1178     }
1179     ret = fstatfs(fd, stbuf);
1180     close_preserve_errno(fd);
1181     return ret;
1182 }
1183 
1184 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
1185                                const char *name, void *value, size_t size)
1186 {
1187     char *path = fs_path->data;
1188 
1189     return v9fs_get_xattr(ctx, path, name, value, size);
1190 }
1191 
1192 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
1193                                 void *value, size_t size)
1194 {
1195     char *path = fs_path->data;
1196 
1197     return v9fs_list_xattr(ctx, path, value, size);
1198 }
1199 
1200 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
1201                            void *value, size_t size, int flags)
1202 {
1203     char *path = fs_path->data;
1204 
1205     return v9fs_set_xattr(ctx, path, name, value, size, flags);
1206 }
1207 
1208 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
1209                               const char *name)
1210 {
1211     char *path = fs_path->data;
1212 
1213     return v9fs_remove_xattr(ctx, path, name);
1214 }
1215 
1216 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
1217                               const char *name, V9fsPath *target)
1218 {
1219     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1220         local_is_mapped_file_metadata(ctx, name)) {
1221         errno = EINVAL;
1222         return -1;
1223     }
1224 
1225     if (dir_path) {
1226         if (!strcmp(name, ".")) {
1227             /* "." relative to "foo/bar" is "foo/bar" */
1228             v9fs_path_copy(target, dir_path);
1229         } else if (!strcmp(name, "..")) {
1230             if (!strcmp(dir_path->data, ".")) {
1231                 /* ".." relative to the root is "." */
1232                 v9fs_path_sprintf(target, ".");
1233             } else {
1234                 char *tmp = g_path_get_dirname(dir_path->data);
1235                 /* Symbolic links are resolved by the client. We can assume
1236                  * that ".." relative to "foo/bar" is equivalent to "foo"
1237                  */
1238                 v9fs_path_sprintf(target, "%s", tmp);
1239                 g_free(tmp);
1240             }
1241         } else {
1242             assert(!strchr(name, '/'));
1243             v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
1244         }
1245     } else if (!strcmp(name, "/") || !strcmp(name, ".") ||
1246                !strcmp(name, "..")) {
1247             /* This is the root fid */
1248         v9fs_path_sprintf(target, ".");
1249     } else {
1250         assert(!strchr(name, '/'));
1251         v9fs_path_sprintf(target, "./%s", name);
1252     }
1253     return 0;
1254 }
1255 
1256 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
1257                           const char *old_name, V9fsPath *newdir,
1258                           const char *new_name)
1259 {
1260     int ret;
1261     int odirfd, ndirfd;
1262 
1263     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1264         (local_is_mapped_file_metadata(ctx, old_name) ||
1265          local_is_mapped_file_metadata(ctx, new_name))) {
1266         errno = EINVAL;
1267         return -1;
1268     }
1269 
1270     odirfd = local_opendir_nofollow(ctx, olddir->data);
1271     if (odirfd == -1) {
1272         return -1;
1273     }
1274 
1275     ndirfd = local_opendir_nofollow(ctx, newdir->data);
1276     if (ndirfd == -1) {
1277         close_preserve_errno(odirfd);
1278         return -1;
1279     }
1280 
1281     ret = renameat(odirfd, old_name, ndirfd, new_name);
1282     if (ret < 0) {
1283         goto out;
1284     }
1285 
1286     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1287         int omap_dirfd, nmap_dirfd;
1288 
1289         ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
1290         if (ret < 0 && errno != EEXIST) {
1291             goto err_undo_rename;
1292         }
1293 
1294         omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
1295         if (omap_dirfd == -1) {
1296             goto err;
1297         }
1298 
1299         nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
1300         if (nmap_dirfd == -1) {
1301             close_preserve_errno(omap_dirfd);
1302             goto err;
1303         }
1304 
1305         /* rename the .virtfs_metadata files */
1306         ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name);
1307         close_preserve_errno(nmap_dirfd);
1308         close_preserve_errno(omap_dirfd);
1309         if (ret < 0 && errno != ENOENT) {
1310             goto err_undo_rename;
1311         }
1312 
1313         ret = 0;
1314     }
1315     goto out;
1316 
1317 err:
1318     ret = -1;
1319 err_undo_rename:
1320     renameat_preserve_errno(ndirfd, new_name, odirfd, old_name);
1321 out:
1322     close_preserve_errno(ndirfd);
1323     close_preserve_errno(odirfd);
1324     return ret;
1325 }
1326 
1327 static void v9fs_path_init_dirname(V9fsPath *path, const char *str)
1328 {
1329     path->data = g_path_get_dirname(str);
1330     path->size = strlen(path->data) + 1;
1331 }
1332 
1333 static int local_rename(FsContext *ctx, const char *oldpath,
1334                         const char *newpath)
1335 {
1336     int err;
1337     char *oname = g_path_get_basename(oldpath);
1338     char *nname = g_path_get_basename(newpath);
1339     V9fsPath olddir, newdir;
1340 
1341     v9fs_path_init_dirname(&olddir, oldpath);
1342     v9fs_path_init_dirname(&newdir, newpath);
1343 
1344     err = local_renameat(ctx, &olddir, oname, &newdir, nname);
1345 
1346     v9fs_path_free(&newdir);
1347     v9fs_path_free(&olddir);
1348     g_free(nname);
1349     g_free(oname);
1350 
1351     return err;
1352 }
1353 
1354 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
1355                           const char *name, int flags)
1356 {
1357     int ret;
1358     int dirfd;
1359 
1360     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1361         local_is_mapped_file_metadata(ctx, name)) {
1362         errno = EINVAL;
1363         return -1;
1364     }
1365 
1366     dirfd = local_opendir_nofollow(ctx, dir->data);
1367     if (dirfd == -1) {
1368         return -1;
1369     }
1370 
1371     ret = local_unlinkat_common(ctx, dirfd, name, flags);
1372     close_preserve_errno(dirfd);
1373     return ret;
1374 }
1375 
1376 #ifdef FS_IOC_GETVERSION
1377 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1378                                 mode_t st_mode, uint64_t *st_gen)
1379 {
1380     int err;
1381     V9fsFidOpenState fid_open;
1382 
1383     /*
1384      * Do not try to open special files like device nodes, fifos etc
1385      * We can get fd for regular files and directories only
1386      */
1387     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1388         errno = ENOTTY;
1389         return -1;
1390     }
1391     err = local_open(ctx, path, O_RDONLY, &fid_open);
1392     if (err < 0) {
1393         return err;
1394     }
1395     err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1396     local_close(ctx, &fid_open);
1397     return err;
1398 }
1399 #endif
1400 
1401 static int local_ioc_getversion_init(FsContext *ctx, LocalData *data, Error **errp)
1402 {
1403 #ifdef FS_IOC_GETVERSION
1404     struct statfs stbuf;
1405 
1406     /*
1407      * use ioc_getversion only if the ioctl is definied
1408      */
1409     if (fstatfs(data->mountfd, &stbuf) < 0) {
1410         error_setg_errno(errp, errno,
1411                          "failed to stat file system at '%s'", ctx->fs_root);
1412         return -1;
1413     }
1414     switch (stbuf.f_type) {
1415     case EXT2_SUPER_MAGIC:
1416     case BTRFS_SUPER_MAGIC:
1417     case REISERFS_SUPER_MAGIC:
1418     case XFS_SUPER_MAGIC:
1419         ctx->exops.get_st_gen = local_ioc_getversion;
1420         break;
1421     }
1422 #endif
1423     return 0;
1424 }
1425 
1426 static int local_init(FsContext *ctx, Error **errp)
1427 {
1428     LocalData *data = g_malloc(sizeof(*data));
1429 
1430     data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
1431     if (data->mountfd == -1) {
1432         error_setg_errno(errp, errno, "failed to open '%s'", ctx->fs_root);
1433         goto err;
1434     }
1435 
1436     if (local_ioc_getversion_init(ctx, data, errp) < 0) {
1437         close(data->mountfd);
1438         goto err;
1439     }
1440 
1441     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1442         ctx->xops = passthrough_xattr_ops;
1443     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1444         ctx->xops = mapped_xattr_ops;
1445     } else if (ctx->export_flags & V9FS_SM_NONE) {
1446         ctx->xops = none_xattr_ops;
1447     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1448         /*
1449          * xattr operation for mapped-file and passthrough
1450          * remain same.
1451          */
1452         ctx->xops = passthrough_xattr_ops;
1453     }
1454     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1455 
1456     ctx->private = data;
1457     return 0;
1458 
1459 err:
1460     g_free(data);
1461     return -1;
1462 }
1463 
1464 static void local_cleanup(FsContext *ctx)
1465 {
1466     LocalData *data = ctx->private;
1467 
1468     if (!data) {
1469         return;
1470     }
1471 
1472     close(data->mountfd);
1473     g_free(data);
1474 }
1475 
1476 static void error_append_security_model_hint(Error **errp)
1477 {
1478     error_append_hint(errp, "Valid options are: security_model="
1479                       "[passthrough|mapped-xattr|mapped-file|none]\n");
1480 }
1481 
1482 static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
1483 {
1484     const char *sec_model = qemu_opt_get(opts, "security_model");
1485     const char *path = qemu_opt_get(opts, "path");
1486     const char *multidevs = qemu_opt_get(opts, "multidevs");
1487     Error *local_err = NULL;
1488 
1489     if (!sec_model) {
1490         error_setg(errp, "security_model property not set");
1491         error_append_security_model_hint(errp);
1492         return -1;
1493     }
1494 
1495     if (!strcmp(sec_model, "passthrough")) {
1496         fse->export_flags |= V9FS_SM_PASSTHROUGH;
1497     } else if (!strcmp(sec_model, "mapped") ||
1498                !strcmp(sec_model, "mapped-xattr")) {
1499         fse->export_flags |= V9FS_SM_MAPPED;
1500     } else if (!strcmp(sec_model, "none")) {
1501         fse->export_flags |= V9FS_SM_NONE;
1502     } else if (!strcmp(sec_model, "mapped-file")) {
1503         fse->export_flags |= V9FS_SM_MAPPED_FILE;
1504     } else {
1505         error_setg(errp, "invalid security_model property '%s'", sec_model);
1506         error_append_security_model_hint(errp);
1507         return -1;
1508     }
1509 
1510     if (multidevs) {
1511         if (!strcmp(multidevs, "remap")) {
1512             fse->export_flags &= ~V9FS_FORBID_MULTIDEVS;
1513             fse->export_flags |= V9FS_REMAP_INODES;
1514         } else if (!strcmp(multidevs, "forbid")) {
1515             fse->export_flags &= ~V9FS_REMAP_INODES;
1516             fse->export_flags |= V9FS_FORBID_MULTIDEVS;
1517         } else if (!strcmp(multidevs, "warn")) {
1518             fse->export_flags &= ~V9FS_FORBID_MULTIDEVS;
1519             fse->export_flags &= ~V9FS_REMAP_INODES;
1520         } else {
1521             error_setg(&local_err, "invalid multidevs property '%s'",
1522                        multidevs);
1523             error_append_hint(&local_err, "Valid options are: multidevs="
1524                               "[remap|forbid|warn]\n");
1525             error_propagate(errp, local_err);
1526             return -1;
1527         }
1528     }
1529 
1530     if (!path) {
1531         error_setg(errp, "path property not set");
1532         return -1;
1533     }
1534 
1535     if (fsdev_throttle_parse_opts(opts, &fse->fst, &local_err)) {
1536         error_propagate_prepend(errp, local_err,
1537                                 "invalid throttle configuration: ");
1538         return -1;
1539     }
1540 
1541     if (fse->export_flags & V9FS_SM_MAPPED ||
1542         fse->export_flags & V9FS_SM_MAPPED_FILE) {
1543         fse->fmode =
1544             qemu_opt_get_number(opts, "fmode", SM_LOCAL_MODE_BITS) & 0777;
1545         fse->dmode =
1546             qemu_opt_get_number(opts, "dmode", SM_LOCAL_DIR_MODE_BITS) & 0777;
1547     } else {
1548         if (qemu_opt_find(opts, "fmode")) {
1549             error_setg(errp, "fmode is only valid for mapped security modes");
1550             return -1;
1551         }
1552         if (qemu_opt_find(opts, "dmode")) {
1553             error_setg(errp, "dmode is only valid for mapped security modes");
1554             return -1;
1555         }
1556     }
1557 
1558     fse->path = g_strdup(path);
1559 
1560     return 0;
1561 }
1562 
1563 FileOperations local_ops = {
1564     .parse_opts = local_parse_opts,
1565     .init  = local_init,
1566     .cleanup = local_cleanup,
1567     .lstat = local_lstat,
1568     .readlink = local_readlink,
1569     .close = local_close,
1570     .closedir = local_closedir,
1571     .open = local_open,
1572     .opendir = local_opendir,
1573     .rewinddir = local_rewinddir,
1574     .telldir = local_telldir,
1575     .readdir = local_readdir,
1576     .seekdir = local_seekdir,
1577     .preadv = local_preadv,
1578     .pwritev = local_pwritev,
1579     .chmod = local_chmod,
1580     .mknod = local_mknod,
1581     .mkdir = local_mkdir,
1582     .fstat = local_fstat,
1583     .open2 = local_open2,
1584     .symlink = local_symlink,
1585     .link = local_link,
1586     .truncate = local_truncate,
1587     .rename = local_rename,
1588     .chown = local_chown,
1589     .utimensat = local_utimensat,
1590     .remove = local_remove,
1591     .fsync = local_fsync,
1592     .statfs = local_statfs,
1593     .lgetxattr = local_lgetxattr,
1594     .llistxattr = local_llistxattr,
1595     .lsetxattr = local_lsetxattr,
1596     .lremovexattr = local_lremovexattr,
1597     .name_to_path = local_name_to_path,
1598     .renameat  = local_renameat,
1599     .unlinkat = local_unlinkat,
1600 };
1601