hw/9pfs/9p-local.c

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