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     struct stat stbuf;
 337     int fd, ret;
 338
 339     /* FIXME: this should be handled with fchmodat(AT_SYMLINK_NOFOLLOW).
 340      * Unfortunately, the linux kernel doesn't implement it yet.
 341      */
 342
 343      /* First, we clear non-racing symlinks out of the way. */
 344     if (fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW)) {
 345         return -1;
 346     }
 347     if (S_ISLNK(stbuf.st_mode)) {
 348         errno = ELOOP;
 349         return -1;
 350     }
 351
 352     /* Access modes are ignored when O_PATH is supported. We try O_RDONLY and
 353      * O_WRONLY for old-systems that don't support O_PATH.
 354      */
 355     fd = openat_file(dirfd, name, O_RDONLY | O_PATH_9P_UTIL, 0);
 356 #if O_PATH_9P_UTIL == 0
 357     if (fd == -1) {
 358         /* In case the file is writable-only and isn't a directory. */
 359         if (errno == EACCES) {
 360             fd = openat_file(dirfd, name, O_WRONLY, 0);
 361         }
 362         if (fd == -1 && errno == EISDIR) {
 363             errno = EACCES;
 364         }
 365     }
 366     if (fd == -1) {
 367         return -1;
 368     }
 369     ret = fchmod(fd, mode);
 370 #else
 371     if (fd == -1) {
 372         return -1;
 373     }
 374
 375     /* Now we handle racing symlinks. */
 376     ret = fstat(fd, &stbuf);
 377     if (!ret) {
 378         if (S_ISLNK(stbuf.st_mode)) {
 379             errno = ELOOP;
 380             ret = -1;
 381         } else {
 382             char *proc_path = g_strdup_printf("/proc/self/fd/%d", fd);
 383             ret = chmod(proc_path, mode);
 384             g_free(proc_path);
 385         }
 386     }
 387 #endif
 388     close_preserve_errno(fd);
 389     return ret;
 390 }
 391
 392 static int local_set_xattrat(int dirfd, const char *path, FsCred *credp)
 393 {
 394     int err;
 395
 396     if (credp->fc_uid != -1) {
 397         uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
 398         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.uid", &tmp_uid,
 399                                    sizeof(uid_t), 0);
 400         if (err) {
 401             return err;
 402         }
 403     }
 404     if (credp->fc_gid != -1) {
 405         uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
 406         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.gid", &tmp_gid,
 407                                    sizeof(gid_t), 0);
 408         if (err) {
 409             return err;
 410         }
 411     }
 412     if (credp->fc_mode != -1) {
 413         uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
 414         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.mode", &tmp_mode,
 415                                    sizeof(mode_t), 0);
 416         if (err) {
 417             return err;
 418         }
 419     }
 420     if (credp->fc_rdev != -1) {
 421         uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
 422         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.rdev", &tmp_rdev,
 423                                    sizeof(dev_t), 0);
 424         if (err) {
 425             return err;
 426         }
 427     }
 428     return 0;
 429 }
 430
 431 static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd,
 432                                       const char *name, FsCred *credp)
 433 {
 434     if (fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
 435                  AT_SYMLINK_NOFOLLOW) < 0) {
 436         /*
 437          * If we fail to change ownership and if we are
 438          * using security model none. Ignore the error
 439          */
 440         if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 441             return -1;
 442         }
 443     }
 444
 445     return fchmodat_nofollow(dirfd, name, credp->fc_mode & 07777);
 446 }
 447
 448 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
 449                               char *buf, size_t bufsz)
 450 {
 451     ssize_t tsize = -1;
 452
 453     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
 454         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 455         int fd;
 456
 457         fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0);
 458         if (fd == -1) {
 459             return -1;
 460         }
 461         do {
 462             tsize = read(fd, (void *)buf, bufsz);
 463         } while (tsize == -1 && errno == EINTR);
 464         close_preserve_errno(fd);
 465     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 466                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 467         char *dirpath = g_path_get_dirname(fs_path->data);
 468         char *name = g_path_get_basename(fs_path->data);
 469         int dirfd;
 470
 471         dirfd = local_opendir_nofollow(fs_ctx, dirpath);
 472         if (dirfd == -1) {
 473             goto out;
 474         }
 475
 476         tsize = readlinkat(dirfd, name, buf, bufsz);
 477         close_preserve_errno(dirfd);
 478     out:
 479         g_free(name);
 480         g_free(dirpath);
 481     }
 482     return tsize;
 483 }
 484
 485 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
 486 {
 487     return close(fs->fd);
 488 }
 489
 490 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 491 {
 492     return closedir(fs->dir.stream);
 493 }
 494
 495 static int local_open(FsContext *ctx, V9fsPath *fs_path,
 496                       int flags, V9fsFidOpenState *fs)
 497 {
 498     int fd;
 499
 500     fd = local_open_nofollow(ctx, fs_path->data, flags, 0);
 501     if (fd == -1) {
 502         return -1;
 503     }
 504     fs->fd = fd;
 505     return fs->fd;
 506 }
 507
 508 static int local_opendir(FsContext *ctx,
 509                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 510 {
 511     int dirfd;
 512     DIR *stream;
 513
 514     dirfd = local_opendir_nofollow(ctx, fs_path->data);
 515     if (dirfd == -1) {
 516         return -1;
 517     }
 518
 519     stream = fdopendir(dirfd);
 520     if (!stream) {
 521         close(dirfd);
 522         return -1;
 523     }
 524     fs->dir.stream = stream;
 525     return 0;
 526 }
 527
 528 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 529 {
 530     rewinddir(fs->dir.stream);
 531 }
 532
 533 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 534 {
 535     return telldir(fs->dir.stream);
 536 }
 537
 538 static bool local_is_mapped_file_metadata(FsContext *fs_ctx, const char *name)
 539 {
 540     return
 541         !strcmp(name, VIRTFS_META_DIR) || !strcmp(name, VIRTFS_META_ROOT_FILE);
 542 }
 543
 544 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs)
 545 {
 546     struct dirent *entry;
 547
 548 again:
 549     entry = readdir(fs->dir.stream);
 550     if (!entry) {
 551         return NULL;
 552     }
 553
 554     if (ctx->export_flags & V9FS_SM_MAPPED) {
 555         entry->d_type = DT_UNKNOWN;
 556     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 557         if (local_is_mapped_file_metadata(ctx, entry->d_name)) {
 558             /* skip the meta data */
 559             goto again;
 560         }
 561         entry->d_type = DT_UNKNOWN;
 562     }
 563
 564     return entry;
 565 }
 566
 567 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 568 {
 569     seekdir(fs->dir.stream, off);
 570 }
 571
 572 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
 573                             const struct iovec *iov,
 574                             int iovcnt, off_t offset)
 575 {
 576 #ifdef CONFIG_PREADV
 577     return preadv(fs->fd, iov, iovcnt, offset);
 578 #else
 579     int err = lseek(fs->fd, offset, SEEK_SET);
 580     if (err == -1) {
 581         return err;
 582     } else {
 583         return readv(fs->fd, iov, iovcnt);
 584     }
 585 #endif
 586 }
 587
 588 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 589                              const struct iovec *iov,
 590                              int iovcnt, off_t offset)
 591 {
 592     ssize_t ret;
 593 #ifdef CONFIG_PREADV
 594     ret = pwritev(fs->fd, iov, iovcnt, offset);
 595 #else
 596     int err = lseek(fs->fd, offset, SEEK_SET);
 597     if (err == -1) {
 598         return err;
 599     } else {
 600         ret = writev(fs->fd, iov, iovcnt);
 601     }
 602 #endif
 603 #ifdef CONFIG_SYNC_FILE_RANGE
 604     if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
 605         /*
 606          * Initiate a writeback. This is not a data integrity sync.
 607          * We want to ensure that we don't leave dirty pages in the cache
 608          * after write when writeout=immediate is sepcified.
 609          */
 610         sync_file_range(fs->fd, offset, ret,
 611                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
 612     }
 613 #endif
 614     return ret;
 615 }
 616
 617 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 618 {
 619     char *dirpath = g_path_get_dirname(fs_path->data);
 620     char *name = g_path_get_basename(fs_path->data);
 621     int ret = -1;
 622     int dirfd;
 623
 624     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
 625     if (dirfd == -1) {
 626         goto out;
 627     }
 628
 629     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 630         ret = local_set_xattrat(dirfd, name, credp);
 631     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 632         ret = local_set_mapped_file_attrat(dirfd, name, credp);
 633     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 634                fs_ctx->export_flags & V9FS_SM_NONE) {
 635         ret = fchmodat_nofollow(dirfd, name, credp->fc_mode);
 636     }
 637     close_preserve_errno(dirfd);
 638
 639 out:
 640     g_free(dirpath);
 641     g_free(name);
 642     return ret;
 643 }
 644
 645 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
 646                        const char *name, FsCred *credp)
 647 {
 648     int err = -1;
 649     int dirfd;
 650
 651     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 652         local_is_mapped_file_metadata(fs_ctx, name)) {
 653         errno = EINVAL;
 654         return -1;
 655     }
 656
 657     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 658     if (dirfd == -1) {
 659         return -1;
 660     }
 661
 662     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 663         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 664         err = mknodat(dirfd, name, fs_ctx->fmode | S_IFREG, 0);
 665         if (err == -1) {
 666             goto out;
 667         }
 668
 669         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 670             err = local_set_xattrat(dirfd, name, credp);
 671         } else {
 672             err = local_set_mapped_file_attrat(dirfd, name, credp);
 673         }
 674         if (err == -1) {
 675             goto err_end;
 676         }
 677     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 678                fs_ctx->export_flags & V9FS_SM_NONE) {
 679         err = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
 680         if (err == -1) {
 681             goto out;
 682         }
 683         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
 684         if (err == -1) {
 685             goto err_end;
 686         }
 687     }
 688     goto out;
 689
 690 err_end:
 691     unlinkat_preserve_errno(dirfd, name, 0);
 692 out:
 693     close_preserve_errno(dirfd);
 694     return err;
 695 }
 696
 697 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
 698                        const char *name, FsCred *credp)
 699 {
 700     int err = -1;
 701     int dirfd;
 702
 703     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 704         local_is_mapped_file_metadata(fs_ctx, name)) {
 705         errno = EINVAL;
 706         return -1;
 707     }
 708
 709     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 710     if (dirfd == -1) {
 711         return -1;
 712     }
 713
 714     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 715         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 716         err = mkdirat(dirfd, name, fs_ctx->dmode);
 717         if (err == -1) {
 718             goto out;
 719         }
 720         credp->fc_mode = credp->fc_mode | S_IFDIR;
 721
 722         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 723             err = local_set_xattrat(dirfd, name, credp);
 724         } else {
 725             err = local_set_mapped_file_attrat(dirfd, name, credp);
 726         }
 727         if (err == -1) {
 728             goto err_end;
 729         }
 730     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 731                fs_ctx->export_flags & V9FS_SM_NONE) {
 732         err = mkdirat(dirfd, name, credp->fc_mode);
 733         if (err == -1) {
 734             goto out;
 735         }
 736         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
 737         if (err == -1) {
 738             goto err_end;
 739         }
 740     }
 741     goto out;
 742
 743 err_end:
 744     unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR);
 745 out:
 746     close_preserve_errno(dirfd);
 747     return err;
 748 }
 749
 750 static int local_fstat(FsContext *fs_ctx, int fid_type,
 751                        V9fsFidOpenState *fs, struct stat *stbuf)
 752 {
 753     int err, fd;
 754
 755     if (fid_type == P9_FID_DIR) {
 756         fd = dirfd(fs->dir.stream);
 757     } else {
 758         fd = fs->fd;
 759     }
 760
 761     err = fstat(fd, stbuf);
 762     if (err) {
 763         return err;
 764     }
 765     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 766         /* Actual credentials are part of extended attrs */
 767         uid_t tmp_uid;
 768         gid_t tmp_gid;
 769         mode_t tmp_mode;
 770         dev_t tmp_dev;
 771
 772         if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
 773             stbuf->st_uid = le32_to_cpu(tmp_uid);
 774         }
 775         if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
 776             stbuf->st_gid = le32_to_cpu(tmp_gid);
 777         }
 778         if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
 779             stbuf->st_mode = le32_to_cpu(tmp_mode);
 780         }
 781         if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
 782             stbuf->st_rdev = le64_to_cpu(tmp_dev);
 783         }
 784     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 785         errno = EOPNOTSUPP;
 786         return -1;
 787     }
 788     return err;
 789 }
 790
 791 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
 792                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 793 {
 794     int fd = -1;
 795     int err = -1;
 796     int dirfd;
 797
 798     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 799         local_is_mapped_file_metadata(fs_ctx, name)) {
 800         errno = EINVAL;
 801         return -1;
 802     }
 803
 804     /*
 805      * Mark all the open to not follow symlinks
 806      */
 807     flags |= O_NOFOLLOW;
 808
 809     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 810     if (dirfd == -1) {
 811         return -1;
 812     }
 813
 814     /* Determine the security model */
 815     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 816         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 817         fd = openat_file(dirfd, name, flags, fs_ctx->fmode);
 818         if (fd == -1) {
 819             goto out;
 820         }
 821         credp->fc_mode = credp->fc_mode|S_IFREG;
 822         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 823             /* Set cleint credentials in xattr */
 824             err = local_set_xattrat(dirfd, name, credp);
 825         } else {
 826             err = local_set_mapped_file_attrat(dirfd, name, credp);
 827         }
 828         if (err == -1) {
 829             goto err_end;
 830         }
 831     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 832                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 833         fd = openat_file(dirfd, name, flags, credp->fc_mode);
 834         if (fd == -1) {
 835             goto out;
 836         }
 837         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
 838         if (err == -1) {
 839             goto err_end;
 840         }
 841     }
 842     err = fd;
 843     fs->fd = fd;
 844     goto out;
 845
 846 err_end:
 847     unlinkat_preserve_errno(dirfd, name,
 848                             flags & O_DIRECTORY ? AT_REMOVEDIR : 0);
 849     close_preserve_errno(fd);
 850 out:
 851     close_preserve_errno(dirfd);
 852     return err;
 853 }
 854
 855
 856 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 857                          V9fsPath *dir_path, const char *name, FsCred *credp)
 858 {
 859     int err = -1;
 860     int dirfd;
 861
 862     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 863         local_is_mapped_file_metadata(fs_ctx, name)) {
 864         errno = EINVAL;
 865         return -1;
 866     }
 867
 868     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 869     if (dirfd == -1) {
 870         return -1;
 871     }
 872
 873     /* Determine the security model */
 874     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 875         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 876         int fd;
 877         ssize_t oldpath_size, write_size;
 878
 879         fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR,
 880                          fs_ctx->fmode);
 881         if (fd == -1) {
 882             goto out;
 883         }
 884         /* Write the oldpath (target) to the file. */
 885         oldpath_size = strlen(oldpath);
 886         do {
 887             write_size = write(fd, (void *)oldpath, oldpath_size);
 888         } while (write_size == -1 && errno == EINTR);
 889         close_preserve_errno(fd);
 890
 891         if (write_size != oldpath_size) {
 892             goto err_end;
 893         }
 894         /* Set cleint credentials in symlink's xattr */
 895         credp->fc_mode = credp->fc_mode | S_IFLNK;
 896
 897         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 898             err = local_set_xattrat(dirfd, name, credp);
 899         } else {
 900             err = local_set_mapped_file_attrat(dirfd, name, credp);
 901         }
 902         if (err == -1) {
 903             goto err_end;
 904         }
 905     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 906                fs_ctx->export_flags & V9FS_SM_NONE) {
 907         err = symlinkat(oldpath, dirfd, name);
 908         if (err) {
 909             goto out;
 910         }
 911         err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
 912                        AT_SYMLINK_NOFOLLOW);
 913         if (err == -1) {
 914             /*
 915              * If we fail to change ownership and if we are
 916              * using security model none. Ignore the error
 917              */
 918             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 919                 goto err_end;
 920             } else {
 921                 err = 0;
 922             }
 923         }
 924     }
 925     goto out;
 926
 927 err_end:
 928     unlinkat_preserve_errno(dirfd, name, 0);
 929 out:
 930     close_preserve_errno(dirfd);
 931     return err;
 932 }
 933
 934 static int local_link(FsContext *ctx, V9fsPath *oldpath,
 935                       V9fsPath *dirpath, const char *name)
 936 {
 937     char *odirpath = g_path_get_dirname(oldpath->data);
 938     char *oname = g_path_get_basename(oldpath->data);
 939     int ret = -1;
 940     int odirfd, ndirfd;
 941
 942     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 943         local_is_mapped_file_metadata(ctx, name)) {
 944         errno = EINVAL;
 945         return -1;
 946     }
 947
 948     odirfd = local_opendir_nofollow(ctx, odirpath);
 949     if (odirfd == -1) {
 950         goto out;
 951     }
 952
 953     ndirfd = local_opendir_nofollow(ctx, dirpath->data);
 954     if (ndirfd == -1) {
 955         close_preserve_errno(odirfd);
 956         goto out;
 957     }
 958
 959     ret = linkat(odirfd, oname, ndirfd, name, 0);
 960     if (ret < 0) {
 961         goto out_close;
 962     }
 963
 964     /* now link the virtfs_metadata files */
 965     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 966         int omap_dirfd, nmap_dirfd;
 967
 968         ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
 969         if (ret < 0 && errno != EEXIST) {
 970             goto err_undo_link;
 971         }
 972
 973         omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
 974         if (omap_dirfd == -1) {
 975             goto err;
 976         }
 977
 978         nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
 979         if (nmap_dirfd == -1) {
 980             close_preserve_errno(omap_dirfd);
 981             goto err;
 982         }
 983
 984         ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0);
 985         close_preserve_errno(nmap_dirfd);
 986         close_preserve_errno(omap_dirfd);
 987         if (ret < 0 && errno != ENOENT) {
 988             goto err_undo_link;
 989         }
 990
 991         ret = 0;
 992     }
 993     goto out_close;
 994
 995 err:
 996     ret = -1;
 997 err_undo_link:
 998     unlinkat_preserve_errno(ndirfd, name, 0);
 999 out_close:
1000     close_preserve_errno(ndirfd);
1001     close_preserve_errno(odirfd);
1002 out:
1003     g_free(oname);
1004     g_free(odirpath);
1005     return ret;
1006 }
1007
1008 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
1009 {
1010     int fd, ret;
1011
1012     fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0);
1013     if (fd == -1) {
1014         return -1;
1015     }
1016     ret = ftruncate(fd, size);
1017     close_preserve_errno(fd);
1018     return ret;
1019 }
1020
1021 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
1022 {
1023     char *dirpath = g_path_get_dirname(fs_path->data);
1024     char *name = g_path_get_basename(fs_path->data);
1025     int ret = -1;
1026     int dirfd;
1027
1028     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
1029     if (dirfd == -1) {
1030         goto out;
1031     }
1032
1033     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
1034         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
1035         (fs_ctx->export_flags & V9FS_SM_NONE)) {
1036         ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
1037                        AT_SYMLINK_NOFOLLOW);
1038     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
1039         ret = local_set_xattrat(dirfd, name, credp);
1040     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1041         ret = local_set_mapped_file_attrat(dirfd, name, credp);
1042     }
1043
1044     close_preserve_errno(dirfd);
1045 out:
1046     g_free(name);
1047     g_free(dirpath);
1048     return ret;
1049 }
1050
1051 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
1052                            const struct timespec *buf)
1053 {
1054     char *dirpath = g_path_get_dirname(fs_path->data);
1055     char *name = g_path_get_basename(fs_path->data);
1056     int dirfd, ret = -1;
1057
1058     dirfd = local_opendir_nofollow(s, dirpath);
1059     if (dirfd == -1) {
1060         goto out;
1061     }
1062
1063     ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW);
1064     close_preserve_errno(dirfd);
1065 out:
1066     g_free(dirpath);
1067     g_free(name);
1068     return ret;
1069 }
1070
1071 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
1072                                  int flags)
1073 {
1074     int ret = -1;
1075
1076     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1077         int map_dirfd;
1078
1079         /* We need to remove the metadata as well:
1080          * - the metadata directory if we're removing a directory
1081          * - the metadata file in the parent's metadata directory
1082          *
1083          * If any of these are missing (ie, ENOENT) then we're probably
1084          * trying to remove something that wasn't created in mapped-file
1085          * mode. We just ignore the error.
1086          */
1087         if (flags == AT_REMOVEDIR) {
1088             int fd;
1089
1090             fd = openat_dir(dirfd, name);
1091             if (fd == -1) {
1092                 goto err_out;
1093             }
1094             ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
1095             close_preserve_errno(fd);
1096             if (ret < 0 && errno != ENOENT) {
1097                 goto err_out;
1098             }
1099         }
1100         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
1101         if (map_dirfd != -1) {
1102             ret = unlinkat(map_dirfd, name, 0);
1103             close_preserve_errno(map_dirfd);
1104             if (ret < 0 && errno != ENOENT) {
1105                 goto err_out;
1106             }
1107         } else if (errno != ENOENT) {
1108             goto err_out;
1109         }
1110     }
1111
1112     ret = unlinkat(dirfd, name, flags);
1113 err_out:
1114     return ret;
1115 }
1116
1117 static int local_remove(FsContext *ctx, const char *path)
1118 {
1119     struct stat stbuf;
1120     char *dirpath = g_path_get_dirname(path);
1121     char *name = g_path_get_basename(path);
1122     int flags = 0;
1123     int dirfd;
1124     int err = -1;
1125
1126     dirfd = local_opendir_nofollow(ctx, dirpath);
1127     if (dirfd == -1) {
1128         goto out;
1129     }
1130
1131     if (fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) {
1132         goto err_out;
1133     }
1134
1135     if (S_ISDIR(stbuf.st_mode)) {
1136         flags |= AT_REMOVEDIR;
1137     }
1138
1139     err = local_unlinkat_common(ctx, dirfd, name, flags);
1140 err_out:
1141     close_preserve_errno(dirfd);
1142 out:
1143     g_free(name);
1144     g_free(dirpath);
1145     return err;
1146 }
1147
1148 static int local_fsync(FsContext *ctx, int fid_type,
1149                        V9fsFidOpenState *fs, int datasync)
1150 {
1151     int fd;
1152
1153     if (fid_type == P9_FID_DIR) {
1154         fd = dirfd(fs->dir.stream);
1155     } else {
1156         fd = fs->fd;
1157     }
1158
1159     if (datasync) {
1160         return qemu_fdatasync(fd);
1161     } else {
1162         return fsync(fd);
1163     }
1164 }
1165
1166 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
1167 {
1168     int fd, ret;
1169
1170     fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0);
1171     if (fd == -1) {
1172         return -1;
1173     }
1174     ret = fstatfs(fd, stbuf);
1175     close_preserve_errno(fd);
1176     return ret;
1177 }
1178
1179 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
1180                                const char *name, void *value, size_t size)
1181 {
1182     char *path = fs_path->data;
1183
1184     return v9fs_get_xattr(ctx, path, name, value, size);
1185 }
1186
1187 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
1188                                 void *value, size_t size)
1189 {
1190     char *path = fs_path->data;
1191
1192     return v9fs_list_xattr(ctx, path, value, size);
1193 }
1194
1195 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
1196                            void *value, size_t size, int flags)
1197 {
1198     char *path = fs_path->data;
1199
1200     return v9fs_set_xattr(ctx, path, name, value, size, flags);
1201 }
1202
1203 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
1204                               const char *name)
1205 {
1206     char *path = fs_path->data;
1207
1208     return v9fs_remove_xattr(ctx, path, name);
1209 }
1210
1211 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
1212                               const char *name, V9fsPath *target)
1213 {
1214     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1215         local_is_mapped_file_metadata(ctx, name)) {
1216         errno = EINVAL;
1217         return -1;
1218     }
1219
1220     if (dir_path) {
1221         if (!strcmp(name, ".")) {
1222             /* "." relative to "foo/bar" is "foo/bar" */
1223             v9fs_path_copy(target, dir_path);
1224         } else if (!strcmp(name, "..")) {
1225             if (!strcmp(dir_path->data, ".")) {
1226                 /* ".." relative to the root is "." */
1227                 v9fs_path_sprintf(target, ".");
1228             } else {
1229                 char *tmp = g_path_get_dirname(dir_path->data);
1230                 /* Symbolic links are resolved by the client. We can assume
1231                  * that ".." relative to "foo/bar" is equivalent to "foo"
1232                  */
1233                 v9fs_path_sprintf(target, "%s", tmp);
1234                 g_free(tmp);
1235             }
1236         } else {
1237             assert(!strchr(name, '/'));
1238             v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
1239         }
1240     } else if (!strcmp(name, "/") || !strcmp(name, ".") ||
1241                !strcmp(name, "..")) {
1242             /* This is the root fid */
1243         v9fs_path_sprintf(target, ".");
1244     } else {
1245         assert(!strchr(name, '/'));
1246         v9fs_path_sprintf(target, "./%s", name);
1247     }
1248     return 0;
1249 }
1250
1251 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
1252                           const char *old_name, V9fsPath *newdir,
1253                           const char *new_name)
1254 {
1255     int ret;
1256     int odirfd, ndirfd;
1257
1258     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1259         (local_is_mapped_file_metadata(ctx, old_name) ||
1260          local_is_mapped_file_metadata(ctx, new_name))) {
1261         errno = EINVAL;
1262         return -1;
1263     }
1264
1265     odirfd = local_opendir_nofollow(ctx, olddir->data);
1266     if (odirfd == -1) {
1267         return -1;
1268     }
1269
1270     ndirfd = local_opendir_nofollow(ctx, newdir->data);
1271     if (ndirfd == -1) {
1272         close_preserve_errno(odirfd);
1273         return -1;
1274     }
1275
1276     ret = renameat(odirfd, old_name, ndirfd, new_name);
1277     if (ret < 0) {
1278         goto out;
1279     }
1280
1281     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1282         int omap_dirfd, nmap_dirfd;
1283
1284         ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
1285         if (ret < 0 && errno != EEXIST) {
1286             goto err_undo_rename;
1287         }
1288
1289         omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
1290         if (omap_dirfd == -1) {
1291             goto err;
1292         }
1293
1294         nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
1295         if (nmap_dirfd == -1) {
1296             close_preserve_errno(omap_dirfd);
1297             goto err;
1298         }
1299
1300         /* rename the .virtfs_metadata files */
1301         ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name);
1302         close_preserve_errno(nmap_dirfd);
1303         close_preserve_errno(omap_dirfd);
1304         if (ret < 0 && errno != ENOENT) {
1305             goto err_undo_rename;
1306         }
1307
1308         ret = 0;
1309     }
1310     goto out;
1311
1312 err:
1313     ret = -1;
1314 err_undo_rename:
1315     renameat_preserve_errno(ndirfd, new_name, odirfd, old_name);
1316 out:
1317     close_preserve_errno(ndirfd);
1318     close_preserve_errno(odirfd);
1319     return ret;
1320 }
1321
1322 static void v9fs_path_init_dirname(V9fsPath *path, const char *str)
1323 {
1324     path->data = g_path_get_dirname(str);
1325     path->size = strlen(path->data) + 1;
1326 }
1327
1328 static int local_rename(FsContext *ctx, const char *oldpath,
1329                         const char *newpath)
1330 {
1331     int err;
1332     char *oname = g_path_get_basename(oldpath);
1333     char *nname = g_path_get_basename(newpath);
1334     V9fsPath olddir, newdir;
1335
1336     v9fs_path_init_dirname(&olddir, oldpath);
1337     v9fs_path_init_dirname(&newdir, newpath);
1338
1339     err = local_renameat(ctx, &olddir, oname, &newdir, nname);
1340
1341     v9fs_path_free(&newdir);
1342     v9fs_path_free(&olddir);
1343     g_free(nname);
1344     g_free(oname);
1345
1346     return err;
1347 }
1348
1349 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
1350                           const char *name, int flags)
1351 {
1352     int ret;
1353     int dirfd;
1354
1355     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1356         local_is_mapped_file_metadata(ctx, name)) {
1357         errno = EINVAL;
1358         return -1;
1359     }
1360
1361     dirfd = local_opendir_nofollow(ctx, dir->data);
1362     if (dirfd == -1) {
1363         return -1;
1364     }
1365
1366     ret = local_unlinkat_common(ctx, dirfd, name, flags);
1367     close_preserve_errno(dirfd);
1368     return ret;
1369 }
1370
1371 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1372                                 mode_t st_mode, uint64_t *st_gen)
1373 {
1374 #ifdef FS_IOC_GETVERSION
1375     int err;
1376     V9fsFidOpenState fid_open;
1377
1378     /*
1379      * Do not try to open special files like device nodes, fifos etc
1380      * We can get fd for regular files and directories only
1381      */
1382     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1383         errno = ENOTTY;
1384         return -1;
1385     }
1386     err = local_open(ctx, path, O_RDONLY, &fid_open);
1387     if (err < 0) {
1388         return err;
1389     }
1390     err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1391     local_close(ctx, &fid_open);
1392     return err;
1393 #else
1394     errno = ENOTTY;
1395     return -1;
1396 #endif
1397 }
1398
1399 static int local_init(FsContext *ctx)
1400 {
1401     struct statfs stbuf;
1402     LocalData *data = g_malloc(sizeof(*data));
1403
1404     data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
1405     if (data->mountfd == -1) {
1406         goto err;
1407     }
1408
1409 #ifdef FS_IOC_GETVERSION
1410     /*
1411      * use ioc_getversion only if the ioctl is definied
1412      */
1413     if (fstatfs(data->mountfd, &stbuf) < 0) {
1414         close_preserve_errno(data->mountfd);
1415         goto err;
1416     }
1417     switch (stbuf.f_type) {
1418     case EXT2_SUPER_MAGIC:
1419     case BTRFS_SUPER_MAGIC:
1420     case REISERFS_SUPER_MAGIC:
1421     case XFS_SUPER_MAGIC:
1422         ctx->exops.get_st_gen = local_ioc_getversion;
1423         break;
1424     }
1425 #endif
1426
1427     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1428         ctx->xops = passthrough_xattr_ops;
1429     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1430         ctx->xops = mapped_xattr_ops;
1431     } else if (ctx->export_flags & V9FS_SM_NONE) {
1432         ctx->xops = none_xattr_ops;
1433     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1434         /*
1435          * xattr operation for mapped-file and passthrough
1436          * remain same.
1437          */
1438         ctx->xops = passthrough_xattr_ops;
1439     }
1440     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1441
1442     ctx->private = data;
1443     return 0;
1444
1445 err:
1446     g_free(data);
1447     return -1;
1448 }
1449
1450 static void local_cleanup(FsContext *ctx)
1451 {
1452     LocalData *data = ctx->private;
1453
1454     close(data->mountfd);
1455     g_free(data);
1456 }
1457
1458 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
1459 {
1460     const char *sec_model = qemu_opt_get(opts, "security_model");
1461     const char *path = qemu_opt_get(opts, "path");
1462     Error *err = NULL;
1463
1464     if (!sec_model) {
1465         error_report("Security model not specified, local fs needs security model");
1466         error_printf("valid options are:"
1467                      "\tsecurity_model=[passthrough|mapped-xattr|mapped-file|none]\n");
1468         return -1;
1469     }
1470
1471     if (!strcmp(sec_model, "passthrough")) {
1472         fse->export_flags |= V9FS_SM_PASSTHROUGH;
1473     } else if (!strcmp(sec_model, "mapped") ||
1474                !strcmp(sec_model, "mapped-xattr")) {
1475         fse->export_flags |= V9FS_SM_MAPPED;
1476     } else if (!strcmp(sec_model, "none")) {
1477         fse->export_flags |= V9FS_SM_NONE;
1478     } else if (!strcmp(sec_model, "mapped-file")) {
1479         fse->export_flags |= V9FS_SM_MAPPED_FILE;
1480     } else {
1481         error_report("Invalid security model %s specified", sec_model);
1482         error_printf("valid options are:"
1483                      "\t[passthrough|mapped-xattr|mapped-file|none]\n");
1484         return -1;
1485     }
1486
1487     if (!path) {
1488         error_report("fsdev: No path specified");
1489         return -1;
1490     }
1491
1492     fsdev_throttle_parse_opts(opts, &fse->fst, &err);
1493     if (err) {
1494         error_reportf_err(err, "Throttle configuration is not valid: ");
1495         return -1;
1496     }
1497
1498     if (fse->export_flags & V9FS_SM_MAPPED ||
1499         fse->export_flags & V9FS_SM_MAPPED_FILE) {
1500         fse->fmode =
1501             qemu_opt_get_number(opts, "fmode", SM_LOCAL_MODE_BITS) & 0777;
1502         fse->dmode =
1503             qemu_opt_get_number(opts, "dmode", SM_LOCAL_DIR_MODE_BITS) & 0777;
1504     } else {
1505         if (qemu_opt_find(opts, "fmode")) {
1506             error_report("fmode is only valid for mapped 9p modes");
1507             return -1;
1508         }
1509         if (qemu_opt_find(opts, "dmode")) {
1510             error_report("dmode is only valid for mapped 9p modes");
1511             return -1;
1512         }
1513     }
1514
1515     fse->path = g_strdup(path);
1516
1517     return 0;
1518 }
1519
1520 FileOperations local_ops = {
1521     .parse_opts = local_parse_opts,
1522     .init  = local_init,
1523     .cleanup = local_cleanup,
1524     .lstat = local_lstat,
1525     .readlink = local_readlink,
1526     .close = local_close,
1527     .closedir = local_closedir,
1528     .open = local_open,
1529     .opendir = local_opendir,
1530     .rewinddir = local_rewinddir,
1531     .telldir = local_telldir,
1532     .readdir = local_readdir,
1533     .seekdir = local_seekdir,
1534     .preadv = local_preadv,
1535     .pwritev = local_pwritev,
1536     .chmod = local_chmod,
1537     .mknod = local_mknod,
1538     .mkdir = local_mkdir,
1539     .fstat = local_fstat,
1540     .open2 = local_open2,
1541     .symlink = local_symlink,
1542     .link = local_link,
1543     .truncate = local_truncate,
1544     .rename = local_rename,
1545     .chown = local_chown,
1546     .utimensat = local_utimensat,
1547     .remove = local_remove,
1548     .fsync = local_fsync,
1549     .statfs = local_statfs,
1550     .lgetxattr = local_lgetxattr,
1551     .llistxattr = local_llistxattr,
1552     .lsetxattr = local_lsetxattr,
1553     .lremovexattr = local_lremovexattr,
1554     .name_to_path = local_name_to_path,
1555     .renameat  = local_renameat,
1556     .unlinkat = local_unlinkat,
1557 };