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  * Not so fast! You might want to read the 9p developer docs first:
  15  * https://wiki.qemu.org/Documentation/9p
  16  */
  17
  18 #include "qemu/osdep.h"
  19 #include "9p.h"
  20 #include "9p-local.h"
  21 #include "9p-xattr.h"
  22 #include "9p-util.h"
  23 #include "fsdev/qemu-fsdev.h"   /* local_ops */
  24 #include <arpa/inet.h>
  25 #include <pwd.h>
  26 #include <grp.h>
  27 #include <sys/socket.h>
  28 #include <sys/un.h>
  29 #include "qemu/xattr.h"
  30 #include "qapi/error.h"
  31 #include "qemu/cutils.h"
  32 #include "qemu/error-report.h"
  33 #include "qemu/option.h"
  34 #include <libgen.h>
  35 #ifdef CONFIG_LINUX
  36 #include <linux/fs.h>
  37 #ifdef CONFIG_LINUX_MAGIC_H
  38 #include <linux/magic.h>
  39 #endif
  40 #endif
  41 #include <sys/ioctl.h>
  42
  43 #ifndef XFS_SUPER_MAGIC
  44 #define XFS_SUPER_MAGIC  0x58465342
  45 #endif
  46 #ifndef EXT2_SUPER_MAGIC
  47 #define EXT2_SUPER_MAGIC 0xEF53
  48 #endif
  49 #ifndef REISERFS_SUPER_MAGIC
  50 #define REISERFS_SUPER_MAGIC 0x52654973
  51 #endif
  52 #ifndef BTRFS_SUPER_MAGIC
  53 #define BTRFS_SUPER_MAGIC 0x9123683E
  54 #endif
  55
  56 typedef struct {
  57     int mountfd;
  58 } LocalData;
  59
  60 int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
  61                         mode_t mode)
  62 {
  63     LocalData *data = fs_ctx->private;
  64     int fd = data->mountfd;
  65
  66     while (*path && fd != -1) {
  67         const char *c;
  68         int next_fd;
  69         char *head;
  70
  71         /* Only relative paths without consecutive slashes */
  72         assert(*path != '/');
  73
  74         head = g_strdup(path);
  75         c = qemu_strchrnul(path, '/');
  76         if (*c) {
  77             /* Intermediate path element */
  78             head[c - path] = 0;
  79             path = c + 1;
  80             next_fd = openat_dir(fd, head);
  81         } else {
  82             /* Rightmost path element */
  83             next_fd = openat_file(fd, head, flags, mode);
  84             path = c;
  85         }
  86         g_free(head);
  87         if (fd != data->mountfd) {
  88             close_preserve_errno(fd);
  89         }
  90         fd = next_fd;
  91     }
  92
  93     assert(fd != data->mountfd);
  94     return fd;
  95 }
  96
  97 int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
  98 {
  99     return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0);
 100 }
 101
 102 static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd,
 103                                     const char *npath)
 104 {
 105     int serrno = errno;
 106     renameat(odirfd, opath, ndirfd, npath);
 107     errno = serrno;
 108 }
 109
 110 static void unlinkat_preserve_errno(int dirfd, const char *path, int flags)
 111 {
 112     int serrno = errno;
 113     unlinkat(dirfd, path, flags);
 114     errno = serrno;
 115 }
 116
 117 #define VIRTFS_META_DIR ".virtfs_metadata"
 118 #define VIRTFS_META_ROOT_FILE VIRTFS_META_DIR "_root"
 119
 120 static FILE *local_fopenat(int dirfd, const char *name, const char *mode)
 121 {
 122     int fd, o_mode = 0;
 123     FILE *fp;
 124     int flags;
 125     /*
 126      * only supports two modes
 127      */
 128     if (mode[0] == 'r') {
 129         flags = O_RDONLY;
 130     } else if (mode[0] == 'w') {
 131         flags = O_WRONLY | O_TRUNC | O_CREAT;
 132         o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
 133     } else {
 134         return NULL;
 135     }
 136     fd = openat_file(dirfd, name, flags, o_mode);
 137     if (fd == -1) {
 138         return NULL;
 139     }
 140     fp = fdopen(fd, mode);
 141     if (!fp) {
 142         close(fd);
 143     }
 144     return fp;
 145 }
 146
 147 #define ATTR_MAX 100
 148 static void local_mapped_file_attr(int dirfd, const char *name,
 149                                    struct stat *stbuf)
 150 {
 151     FILE *fp;
 152     char buf[ATTR_MAX];
 153     int map_dirfd;
 154
 155     if (strcmp(name, ".")) {
 156         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
 157         if (map_dirfd == -1) {
 158             return;
 159         }
 160
 161         fp = local_fopenat(map_dirfd, name, "r");
 162         close_preserve_errno(map_dirfd);
 163     } else {
 164         fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "r");
 165     }
 166     if (!fp) {
 167         return;
 168     }
 169     memset(buf, 0, ATTR_MAX);
 170     while (fgets(buf, ATTR_MAX, fp)) {
 171         if (!strncmp(buf, "virtfs.uid", 10)) {
 172             stbuf->st_uid = atoi(buf + 11);
 173         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 174             stbuf->st_gid = atoi(buf + 11);
 175         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 176             stbuf->st_mode = atoi(buf + 12);
 177         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 178             stbuf->st_rdev = atoi(buf + 12);
 179         }
 180         memset(buf, 0, ATTR_MAX);
 181     }
 182     fclose(fp);
 183 }
 184
 185 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
 186 {
 187     int err = -1;
 188     char *dirpath = g_path_get_dirname(fs_path->data);
 189     char *name = g_path_get_basename(fs_path->data);
 190     int dirfd;
 191
 192     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
 193     if (dirfd == -1) {
 194         goto out;
 195     }
 196
 197     err = fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW);
 198     if (err) {
 199         goto err_out;
 200     }
 201     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 202         /* Actual credentials are part of extended attrs */
 203         uid_t tmp_uid;
 204         gid_t tmp_gid;
 205         mode_t tmp_mode;
 206         dev_t tmp_dev;
 207
 208         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.uid", &tmp_uid,
 209                                  sizeof(uid_t)) > 0) {
 210             stbuf->st_uid = le32_to_cpu(tmp_uid);
 211         }
 212         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.gid", &tmp_gid,
 213                                  sizeof(gid_t)) > 0) {
 214             stbuf->st_gid = le32_to_cpu(tmp_gid);
 215         }
 216         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.mode", &tmp_mode,
 217                                  sizeof(mode_t)) > 0) {
 218             stbuf->st_mode = le32_to_cpu(tmp_mode);
 219         }
 220         if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.rdev", &tmp_dev,
 221                                  sizeof(dev_t)) > 0) {
 222             stbuf->st_rdev = le64_to_cpu(tmp_dev);
 223         }
 224     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 225         local_mapped_file_attr(dirfd, name, stbuf);
 226     }
 227
 228 err_out:
 229     close_preserve_errno(dirfd);
 230 out:
 231     g_free(name);
 232     g_free(dirpath);
 233     return err;
 234 }
 235
 236 static int local_set_mapped_file_attrat(int dirfd, const char *name,
 237                                         FsCred *credp)
 238 {
 239     FILE *fp;
 240     int ret;
 241     char buf[ATTR_MAX];
 242     int uid = -1, gid = -1, mode = -1, rdev = -1;
 243     int map_dirfd = -1, map_fd;
 244     bool is_root = !strcmp(name, ".");
 245
 246     if (is_root) {
 247         fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "r");
 248         if (!fp) {
 249             if (errno == ENOENT) {
 250                 goto update_map_file;
 251             } else {
 252                 return -1;
 253             }
 254         }
 255     } else {
 256         ret = mkdirat(dirfd, VIRTFS_META_DIR, 0700);
 257         if (ret < 0 && errno != EEXIST) {
 258             return -1;
 259         }
 260
 261         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
 262         if (map_dirfd == -1) {
 263             return -1;
 264         }
 265
 266         fp = local_fopenat(map_dirfd, name, "r");
 267         if (!fp) {
 268             if (errno == ENOENT) {
 269                 goto update_map_file;
 270             } else {
 271                 close_preserve_errno(map_dirfd);
 272                 return -1;
 273             }
 274         }
 275     }
 276     memset(buf, 0, ATTR_MAX);
 277     while (fgets(buf, ATTR_MAX, fp)) {
 278         if (!strncmp(buf, "virtfs.uid", 10)) {
 279             uid = atoi(buf + 11);
 280         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 281             gid = atoi(buf + 11);
 282         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 283             mode = atoi(buf + 12);
 284         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 285             rdev = atoi(buf + 12);
 286         }
 287         memset(buf, 0, ATTR_MAX);
 288     }
 289     fclose(fp);
 290
 291 update_map_file:
 292     if (is_root) {
 293         fp = local_fopenat(dirfd, VIRTFS_META_ROOT_FILE, "w");
 294     } else {
 295         fp = local_fopenat(map_dirfd, name, "w");
 296         /* We can't go this far with map_dirfd not being a valid file descriptor
 297          * but some versions of gcc aren't smart enough to see it.
 298          */
 299         if (map_dirfd != -1) {
 300             close_preserve_errno(map_dirfd);
 301         }
 302     }
 303     if (!fp) {
 304         return -1;
 305     }
 306
 307     map_fd = fileno(fp);
 308     assert(map_fd != -1);
 309     ret = fchmod(map_fd, 0600);
 310     assert(ret == 0);
 311
 312     if (credp->fc_uid != -1) {
 313         uid = credp->fc_uid;
 314     }
 315     if (credp->fc_gid != -1) {
 316         gid = credp->fc_gid;
 317     }
 318     if (credp->fc_mode != (mode_t)-1) {
 319         mode = credp->fc_mode;
 320     }
 321     if (credp->fc_rdev != -1) {
 322         rdev = credp->fc_rdev;
 323     }
 324
 325     if (uid != -1) {
 326         fprintf(fp, "virtfs.uid=%d\n", uid);
 327     }
 328     if (gid != -1) {
 329         fprintf(fp, "virtfs.gid=%d\n", gid);
 330     }
 331     if (mode != -1) {
 332         fprintf(fp, "virtfs.mode=%d\n", mode);
 333     }
 334     if (rdev != -1) {
 335         fprintf(fp, "virtfs.rdev=%d\n", rdev);
 336     }
 337     fclose(fp);
 338
 339     return 0;
 340 }
 341
 342 static int fchmodat_nofollow(int dirfd, const char *name, mode_t mode)
 343 {
 344     struct stat stbuf;
 345     int fd, ret;
 346
 347     /* FIXME: this should be handled with fchmodat(AT_SYMLINK_NOFOLLOW).
 348      * Unfortunately, the linux kernel doesn't implement it yet.
 349      */
 350
 351      /* First, we clear non-racing symlinks out of the way. */
 352     if (fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW)) {
 353         return -1;
 354     }
 355     if (S_ISLNK(stbuf.st_mode)) {
 356         errno = ELOOP;
 357         return -1;
 358     }
 359
 360     fd = openat_file(dirfd, name, O_RDONLY | O_PATH_9P_UTIL | O_NOFOLLOW, 0);
 361 #if O_PATH_9P_UTIL == 0
 362     /* Fallback for systems that don't support O_PATH: we depend on the file
 363      * being readable or writable.
 364      */
 365     if (fd == -1) {
 366         /* In case the file is writable-only and isn't a directory. */
 367         if (errno == EACCES) {
 368             fd = openat_file(dirfd, name, O_WRONLY, 0);
 369         }
 370         if (fd == -1 && errno == EISDIR) {
 371             errno = EACCES;
 372         }
 373     }
 374     if (fd == -1) {
 375         return -1;
 376     }
 377     ret = fchmod(fd, mode);
 378 #else
 379     /* Access modes are ignored when O_PATH is supported. If name is a symbolic
 380      * link, O_PATH | O_NOFOLLOW causes openat(2) to return a file descriptor
 381      * referring to the symbolic link.
 382      */
 383     if (fd == -1) {
 384         return -1;
 385     }
 386
 387     /* Now we handle racing symlinks. */
 388     ret = fstat(fd, &stbuf);
 389     if (!ret) {
 390         if (S_ISLNK(stbuf.st_mode)) {
 391             errno = ELOOP;
 392             ret = -1;
 393         } else {
 394             char *proc_path = g_strdup_printf("/proc/self/fd/%d", fd);
 395             ret = chmod(proc_path, mode);
 396             g_free(proc_path);
 397         }
 398     }
 399 #endif
 400     close_preserve_errno(fd);
 401     return ret;
 402 }
 403
 404 static int local_set_xattrat(int dirfd, const char *path, FsCred *credp)
 405 {
 406     int err;
 407
 408     if (credp->fc_uid != -1) {
 409         uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
 410         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.uid", &tmp_uid,
 411                                    sizeof(uid_t), 0);
 412         if (err) {
 413             return err;
 414         }
 415     }
 416     if (credp->fc_gid != -1) {
 417         uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
 418         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.gid", &tmp_gid,
 419                                    sizeof(gid_t), 0);
 420         if (err) {
 421             return err;
 422         }
 423     }
 424     if (credp->fc_mode != (mode_t)-1) {
 425         uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
 426         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.mode", &tmp_mode,
 427                                    sizeof(mode_t), 0);
 428         if (err) {
 429             return err;
 430         }
 431     }
 432     if (credp->fc_rdev != -1) {
 433         uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
 434         err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.rdev", &tmp_rdev,
 435                                    sizeof(dev_t), 0);
 436         if (err) {
 437             return err;
 438         }
 439     }
 440     return 0;
 441 }
 442
 443 static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd,
 444                                       const char *name, FsCred *credp)
 445 {
 446     if (fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
 447                  AT_SYMLINK_NOFOLLOW) < 0) {
 448         /*
 449          * If we fail to change ownership and if we are
 450          * using security model none. Ignore the error
 451          */
 452         if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 453             return -1;
 454         }
 455     }
 456
 457     return fchmodat_nofollow(dirfd, name, credp->fc_mode & 07777);
 458 }
 459
 460 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
 461                               char *buf, size_t bufsz)
 462 {
 463     ssize_t tsize = -1;
 464
 465     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
 466         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 467         int fd;
 468
 469         fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0);
 470         if (fd == -1) {
 471             return -1;
 472         }
 473         do {
 474             tsize = read(fd, (void *)buf, bufsz);
 475         } while (tsize == -1 && errno == EINTR);
 476         close_preserve_errno(fd);
 477     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 478                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 479         char *dirpath = g_path_get_dirname(fs_path->data);
 480         char *name = g_path_get_basename(fs_path->data);
 481         int dirfd;
 482
 483         dirfd = local_opendir_nofollow(fs_ctx, dirpath);
 484         if (dirfd == -1) {
 485             goto out;
 486         }
 487
 488         tsize = readlinkat(dirfd, name, buf, bufsz);
 489         close_preserve_errno(dirfd);
 490     out:
 491         g_free(name);
 492         g_free(dirpath);
 493     }
 494     return tsize;
 495 }
 496
 497 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
 498 {
 499     return close(fs->fd);
 500 }
 501
 502 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 503 {
 504     return closedir(fs->dir.stream);
 505 }
 506
 507 static int local_open(FsContext *ctx, V9fsPath *fs_path,
 508                       int flags, V9fsFidOpenState *fs)
 509 {
 510     int fd;
 511
 512     fd = local_open_nofollow(ctx, fs_path->data, flags, 0);
 513     if (fd == -1) {
 514         return -1;
 515     }
 516     fs->fd = fd;
 517     return fs->fd;
 518 }
 519
 520 static int local_opendir(FsContext *ctx,
 521                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 522 {
 523     int dirfd;
 524     DIR *stream;
 525
 526     dirfd = local_opendir_nofollow(ctx, fs_path->data);
 527     if (dirfd == -1) {
 528         return -1;
 529     }
 530
 531     stream = fdopendir(dirfd);
 532     if (!stream) {
 533         close(dirfd);
 534         return -1;
 535     }
 536     fs->dir.stream = stream;
 537     return 0;
 538 }
 539
 540 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 541 {
 542     rewinddir(fs->dir.stream);
 543 }
 544
 545 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 546 {
 547     return telldir(fs->dir.stream);
 548 }
 549
 550 static bool local_is_mapped_file_metadata(FsContext *fs_ctx, const char *name)
 551 {
 552     return
 553         !strcmp(name, VIRTFS_META_DIR) || !strcmp(name, VIRTFS_META_ROOT_FILE);
 554 }
 555
 556 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs)
 557 {
 558     struct dirent *entry;
 559
 560 again:
 561     entry = readdir(fs->dir.stream);
 562     if (!entry) {
 563         return NULL;
 564     }
 565 #ifdef CONFIG_DARWIN
 566     int off;
 567     off = telldir(fs->dir.stream);
 568     /* If telldir fails, fail the entire readdir call */
 569     if (off < 0) {
 570         return NULL;
 571     }
 572     entry->d_seekoff = off;
 573 #endif
 574
 575     if (ctx->export_flags & V9FS_SM_MAPPED) {
 576         entry->d_type = DT_UNKNOWN;
 577     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 578         if (local_is_mapped_file_metadata(ctx, entry->d_name)) {
 579             /* skip the meta data */
 580             goto again;
 581         }
 582         entry->d_type = DT_UNKNOWN;
 583     }
 584
 585     return entry;
 586 }
 587
 588 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 589 {
 590     seekdir(fs->dir.stream, off);
 591 }
 592
 593 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
 594                             const struct iovec *iov,
 595                             int iovcnt, off_t offset)
 596 {
 597 #ifdef CONFIG_PREADV
 598     return preadv(fs->fd, iov, iovcnt, offset);
 599 #else
 600     int err = lseek(fs->fd, offset, SEEK_SET);
 601     if (err == -1) {
 602         return err;
 603     } else {
 604         return readv(fs->fd, iov, iovcnt);
 605     }
 606 #endif
 607 }
 608
 609 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 610                              const struct iovec *iov,
 611                              int iovcnt, off_t offset)
 612 {
 613     ssize_t ret;
 614 #ifdef CONFIG_PREADV
 615     ret = pwritev(fs->fd, iov, iovcnt, offset);
 616 #else
 617     int err = lseek(fs->fd, offset, SEEK_SET);
 618     if (err == -1) {
 619         return err;
 620     } else {
 621         ret = writev(fs->fd, iov, iovcnt);
 622     }
 623 #endif
 624 #ifdef CONFIG_SYNC_FILE_RANGE
 625     if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
 626         /*
 627          * Initiate a writeback. This is not a data integrity sync.
 628          * We want to ensure that we don't leave dirty pages in the cache
 629          * after write when writeout=immediate is sepcified.
 630          */
 631         sync_file_range(fs->fd, offset, ret,
 632                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
 633     }
 634 #endif
 635     return ret;
 636 }
 637
 638 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 639 {
 640     char *dirpath = g_path_get_dirname(fs_path->data);
 641     char *name = g_path_get_basename(fs_path->data);
 642     int ret = -1;
 643     int dirfd;
 644
 645     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
 646     if (dirfd == -1) {
 647         goto out;
 648     }
 649
 650     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 651         ret = local_set_xattrat(dirfd, name, credp);
 652     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 653         ret = local_set_mapped_file_attrat(dirfd, name, credp);
 654     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 655                fs_ctx->export_flags & V9FS_SM_NONE) {
 656         ret = fchmodat_nofollow(dirfd, name, credp->fc_mode);
 657     }
 658     close_preserve_errno(dirfd);
 659
 660 out:
 661     g_free(dirpath);
 662     g_free(name);
 663     return ret;
 664 }
 665
 666 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
 667                        const char *name, FsCred *credp)
 668 {
 669     int err = -1;
 670     int dirfd;
 671
 672     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 673         local_is_mapped_file_metadata(fs_ctx, name)) {
 674         errno = EINVAL;
 675         return -1;
 676     }
 677
 678     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 679     if (dirfd == -1) {
 680         return -1;
 681     }
 682
 683     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 684         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 685         err = qemu_mknodat(dirfd, name, fs_ctx->fmode | S_IFREG, 0);
 686         if (err == -1) {
 687             goto out;
 688         }
 689
 690         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 691             err = local_set_xattrat(dirfd, name, credp);
 692         } else {
 693             err = local_set_mapped_file_attrat(dirfd, name, credp);
 694         }
 695         if (err == -1) {
 696             goto err_end;
 697         }
 698     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 699                fs_ctx->export_flags & V9FS_SM_NONE) {
 700         err = qemu_mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
 701         if (err == -1) {
 702             goto out;
 703         }
 704         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
 705         if (err == -1) {
 706             goto err_end;
 707         }
 708     }
 709     goto out;
 710
 711 err_end:
 712     unlinkat_preserve_errno(dirfd, name, 0);
 713 out:
 714     close_preserve_errno(dirfd);
 715     return err;
 716 }
 717
 718 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
 719                        const char *name, FsCred *credp)
 720 {
 721     int err = -1;
 722     int dirfd;
 723
 724     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 725         local_is_mapped_file_metadata(fs_ctx, name)) {
 726         errno = EINVAL;
 727         return -1;
 728     }
 729
 730     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 731     if (dirfd == -1) {
 732         return -1;
 733     }
 734
 735     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 736         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 737         err = mkdirat(dirfd, name, fs_ctx->dmode);
 738         if (err == -1) {
 739             goto out;
 740         }
 741         credp->fc_mode = credp->fc_mode | S_IFDIR;
 742
 743         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 744             err = local_set_xattrat(dirfd, name, credp);
 745         } else {
 746             err = local_set_mapped_file_attrat(dirfd, name, credp);
 747         }
 748         if (err == -1) {
 749             goto err_end;
 750         }
 751     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 752                fs_ctx->export_flags & V9FS_SM_NONE) {
 753         err = mkdirat(dirfd, name, credp->fc_mode);
 754         if (err == -1) {
 755             goto out;
 756         }
 757         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
 758         if (err == -1) {
 759             goto err_end;
 760         }
 761     }
 762     goto out;
 763
 764 err_end:
 765     unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR);
 766 out:
 767     close_preserve_errno(dirfd);
 768     return err;
 769 }
 770
 771 static int local_fstat(FsContext *fs_ctx, int fid_type,
 772                        V9fsFidOpenState *fs, struct stat *stbuf)
 773 {
 774     int err, fd;
 775
 776     if (fid_type == P9_FID_DIR) {
 777         fd = dirfd(fs->dir.stream);
 778     } else {
 779         fd = fs->fd;
 780     }
 781
 782     err = fstat(fd, stbuf);
 783     if (err) {
 784         return err;
 785     }
 786     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 787         /* Actual credentials are part of extended attrs */
 788         uid_t tmp_uid;
 789         gid_t tmp_gid;
 790         mode_t tmp_mode;
 791         dev_t tmp_dev;
 792
 793         if (qemu_fgetxattr(fd, "user.virtfs.uid",
 794                            &tmp_uid, sizeof(uid_t)) > 0) {
 795             stbuf->st_uid = le32_to_cpu(tmp_uid);
 796         }
 797         if (qemu_fgetxattr(fd, "user.virtfs.gid",
 798                            &tmp_gid, sizeof(gid_t)) > 0) {
 799             stbuf->st_gid = le32_to_cpu(tmp_gid);
 800         }
 801         if (qemu_fgetxattr(fd, "user.virtfs.mode",
 802                            &tmp_mode, sizeof(mode_t)) > 0) {
 803             stbuf->st_mode = le32_to_cpu(tmp_mode);
 804         }
 805         if (qemu_fgetxattr(fd, "user.virtfs.rdev",
 806                            &tmp_dev, sizeof(dev_t)) > 0) {
 807             stbuf->st_rdev = le64_to_cpu(tmp_dev);
 808         }
 809     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 810         errno = EOPNOTSUPP;
 811         return -1;
 812     }
 813     return err;
 814 }
 815
 816 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
 817                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 818 {
 819     int fd = -1;
 820     int err = -1;
 821     int dirfd;
 822
 823     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 824         local_is_mapped_file_metadata(fs_ctx, name)) {
 825         errno = EINVAL;
 826         return -1;
 827     }
 828
 829     /*
 830      * Mark all the open to not follow symlinks
 831      */
 832     flags |= O_NOFOLLOW;
 833
 834     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 835     if (dirfd == -1) {
 836         return -1;
 837     }
 838
 839     /* Determine the security model */
 840     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 841         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 842         fd = openat_file(dirfd, name, flags, fs_ctx->fmode);
 843         if (fd == -1) {
 844             goto out;
 845         }
 846         credp->fc_mode = credp->fc_mode | S_IFREG;
 847         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 848             /* Set cleint credentials in xattr */
 849             err = local_set_xattrat(dirfd, name, credp);
 850         } else {
 851             err = local_set_mapped_file_attrat(dirfd, name, credp);
 852         }
 853         if (err == -1) {
 854             goto err_end;
 855         }
 856     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 857                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 858         fd = openat_file(dirfd, name, flags, credp->fc_mode);
 859         if (fd == -1) {
 860             goto out;
 861         }
 862         err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
 863         if (err == -1) {
 864             goto err_end;
 865         }
 866     }
 867     err = fd;
 868     fs->fd = fd;
 869     goto out;
 870
 871 err_end:
 872     unlinkat_preserve_errno(dirfd, name,
 873                             flags & O_DIRECTORY ? AT_REMOVEDIR : 0);
 874     close_preserve_errno(fd);
 875 out:
 876     close_preserve_errno(dirfd);
 877     return err;
 878 }
 879
 880
 881 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 882                          V9fsPath *dir_path, const char *name, FsCred *credp)
 883 {
 884     int err = -1;
 885     int dirfd;
 886
 887     if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 888         local_is_mapped_file_metadata(fs_ctx, name)) {
 889         errno = EINVAL;
 890         return -1;
 891     }
 892
 893     dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
 894     if (dirfd == -1) {
 895         return -1;
 896     }
 897
 898     /* Determine the security model */
 899     if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
 900         fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 901         int fd;
 902         ssize_t oldpath_size, write_size;
 903
 904         fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR,
 905                          fs_ctx->fmode);
 906         if (fd == -1) {
 907             goto out;
 908         }
 909         /* Write the oldpath (target) to the file. */
 910         oldpath_size = strlen(oldpath);
 911         do {
 912             write_size = write(fd, (void *)oldpath, oldpath_size);
 913         } while (write_size == -1 && errno == EINTR);
 914         close_preserve_errno(fd);
 915
 916         if (write_size != oldpath_size) {
 917             goto err_end;
 918         }
 919         /* Set cleint credentials in symlink's xattr */
 920         credp->fc_mode = credp->fc_mode | S_IFLNK;
 921
 922         if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 923             err = local_set_xattrat(dirfd, name, credp);
 924         } else {
 925             err = local_set_mapped_file_attrat(dirfd, name, credp);
 926         }
 927         if (err == -1) {
 928             goto err_end;
 929         }
 930     } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
 931                fs_ctx->export_flags & V9FS_SM_NONE) {
 932         err = symlinkat(oldpath, dirfd, name);
 933         if (err) {
 934             goto out;
 935         }
 936         err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
 937                        AT_SYMLINK_NOFOLLOW);
 938         if (err == -1) {
 939             /*
 940              * If we fail to change ownership and if we are
 941              * using security model none. Ignore the error
 942              */
 943             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 944                 goto err_end;
 945             } else {
 946                 err = 0;
 947             }
 948         }
 949     }
 950     goto out;
 951
 952 err_end:
 953     unlinkat_preserve_errno(dirfd, name, 0);
 954 out:
 955     close_preserve_errno(dirfd);
 956     return err;
 957 }
 958
 959 static int local_link(FsContext *ctx, V9fsPath *oldpath,
 960                       V9fsPath *dirpath, const char *name)
 961 {
 962     char *odirpath = g_path_get_dirname(oldpath->data);
 963     char *oname = g_path_get_basename(oldpath->data);
 964     int ret = -1;
 965     int odirfd, ndirfd;
 966
 967     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
 968         local_is_mapped_file_metadata(ctx, name)) {
 969         errno = EINVAL;
 970         goto out;
 971     }
 972
 973     odirfd = local_opendir_nofollow(ctx, odirpath);
 974     if (odirfd == -1) {
 975         goto out;
 976     }
 977
 978     ndirfd = local_opendir_nofollow(ctx, dirpath->data);
 979     if (ndirfd == -1) {
 980         close_preserve_errno(odirfd);
 981         goto out;
 982     }
 983
 984     ret = linkat(odirfd, oname, ndirfd, name, 0);
 985     if (ret < 0) {
 986         goto out_close;
 987     }
 988
 989     /* now link the virtfs_metadata files */
 990     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 991         int omap_dirfd, nmap_dirfd;
 992
 993         ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
 994         if (ret < 0 && errno != EEXIST) {
 995             goto err_undo_link;
 996         }
 997
 998         omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
 999         if (omap_dirfd == -1) {
1000             goto err;
1001         }
1002
1003         nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
1004         if (nmap_dirfd == -1) {
1005             close_preserve_errno(omap_dirfd);
1006             goto err;
1007         }
1008
1009         ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0);
1010         close_preserve_errno(nmap_dirfd);
1011         close_preserve_errno(omap_dirfd);
1012         if (ret < 0 && errno != ENOENT) {
1013             goto err_undo_link;
1014         }
1015
1016         ret = 0;
1017     }
1018     goto out_close;
1019
1020 err:
1021     ret = -1;
1022 err_undo_link:
1023     unlinkat_preserve_errno(ndirfd, name, 0);
1024 out_close:
1025     close_preserve_errno(ndirfd);
1026     close_preserve_errno(odirfd);
1027 out:
1028     g_free(oname);
1029     g_free(odirpath);
1030     return ret;
1031 }
1032
1033 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
1034 {
1035     int fd, ret;
1036
1037     fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0);
1038     if (fd == -1) {
1039         return -1;
1040     }
1041     ret = ftruncate(fd, size);
1042     close_preserve_errno(fd);
1043     return ret;
1044 }
1045
1046 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
1047 {
1048     char *dirpath = g_path_get_dirname(fs_path->data);
1049     char *name = g_path_get_basename(fs_path->data);
1050     int ret = -1;
1051     int dirfd;
1052
1053     dirfd = local_opendir_nofollow(fs_ctx, dirpath);
1054     if (dirfd == -1) {
1055         goto out;
1056     }
1057
1058     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
1059         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
1060         (fs_ctx->export_flags & V9FS_SM_NONE)) {
1061         ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
1062                        AT_SYMLINK_NOFOLLOW);
1063     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
1064         ret = local_set_xattrat(dirfd, name, credp);
1065     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1066         ret = local_set_mapped_file_attrat(dirfd, name, credp);
1067     }
1068
1069     close_preserve_errno(dirfd);
1070 out:
1071     g_free(name);
1072     g_free(dirpath);
1073     return ret;
1074 }
1075
1076 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
1077                            const struct timespec *buf)
1078 {
1079     char *dirpath = g_path_get_dirname(fs_path->data);
1080     char *name = g_path_get_basename(fs_path->data);
1081     int dirfd, ret = -1;
1082
1083     dirfd = local_opendir_nofollow(s, dirpath);
1084     if (dirfd == -1) {
1085         goto out;
1086     }
1087
1088     ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW);
1089     close_preserve_errno(dirfd);
1090 out:
1091     g_free(dirpath);
1092     g_free(name);
1093     return ret;
1094 }
1095
1096 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
1097                                  int flags)
1098 {
1099     int ret;
1100
1101     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1102         int map_dirfd;
1103
1104         /* We need to remove the metadata as well:
1105          * - the metadata directory if we're removing a directory
1106          * - the metadata file in the parent's metadata directory
1107          *
1108          * If any of these are missing (ie, ENOENT) then we're probably
1109          * trying to remove something that wasn't created in mapped-file
1110          * mode. We just ignore the error.
1111          */
1112         if (flags == AT_REMOVEDIR) {
1113             int fd;
1114
1115             fd = openat_dir(dirfd, name);
1116             if (fd == -1) {
1117                 return -1;
1118             }
1119             ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
1120             close_preserve_errno(fd);
1121             if (ret < 0 && errno != ENOENT) {
1122                 return -1;
1123             }
1124         }
1125         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
1126         if (map_dirfd != -1) {
1127             ret = unlinkat(map_dirfd, name, 0);
1128             close_preserve_errno(map_dirfd);
1129             if (ret < 0 && errno != ENOENT) {
1130                 return -1;
1131             }
1132         } else if (errno != ENOENT) {
1133             return -1;
1134         }
1135     }
1136
1137     return unlinkat(dirfd, name, flags);
1138 }
1139
1140 static int local_remove(FsContext *ctx, const char *path)
1141 {
1142     struct stat stbuf;
1143     char *dirpath = g_path_get_dirname(path);
1144     char *name = g_path_get_basename(path);
1145     int flags = 0;
1146     int dirfd;
1147     int err = -1;
1148
1149     dirfd = local_opendir_nofollow(ctx, dirpath);
1150     if (dirfd == -1) {
1151         goto out;
1152     }
1153
1154     if (fstatat(dirfd, name, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) {
1155         goto err_out;
1156     }
1157
1158     if (S_ISDIR(stbuf.st_mode)) {
1159         flags |= AT_REMOVEDIR;
1160     }
1161
1162     err = local_unlinkat_common(ctx, dirfd, name, flags);
1163 err_out:
1164     close_preserve_errno(dirfd);
1165 out:
1166     g_free(name);
1167     g_free(dirpath);
1168     return err;
1169 }
1170
1171 static int local_fsync(FsContext *ctx, int fid_type,
1172                        V9fsFidOpenState *fs, int datasync)
1173 {
1174     int fd;
1175
1176     if (fid_type == P9_FID_DIR) {
1177         fd = dirfd(fs->dir.stream);
1178     } else {
1179         fd = fs->fd;
1180     }
1181
1182     if (datasync) {
1183         return qemu_fdatasync(fd);
1184     } else {
1185         return fsync(fd);
1186     }
1187 }
1188
1189 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
1190 {
1191     int fd, ret;
1192
1193     fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0);
1194     if (fd == -1) {
1195         return -1;
1196     }
1197     ret = fstatfs(fd, stbuf);
1198     close_preserve_errno(fd);
1199     return ret;
1200 }
1201
1202 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
1203                                const char *name, void *value, size_t size)
1204 {
1205     char *path = fs_path->data;
1206
1207     return v9fs_get_xattr(ctx, path, name, value, size);
1208 }
1209
1210 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
1211                                 void *value, size_t size)
1212 {
1213     char *path = fs_path->data;
1214
1215     return v9fs_list_xattr(ctx, path, value, size);
1216 }
1217
1218 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
1219                            void *value, size_t size, int flags)
1220 {
1221     char *path = fs_path->data;
1222
1223     return v9fs_set_xattr(ctx, path, name, value, size, flags);
1224 }
1225
1226 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
1227                               const char *name)
1228 {
1229     char *path = fs_path->data;
1230
1231     return v9fs_remove_xattr(ctx, path, name);
1232 }
1233
1234 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
1235                               const char *name, V9fsPath *target)
1236 {
1237     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1238         local_is_mapped_file_metadata(ctx, name)) {
1239         errno = EINVAL;
1240         return -1;
1241     }
1242
1243     if (dir_path) {
1244         if (!strcmp(name, ".")) {
1245             /* "." relative to "foo/bar" is "foo/bar" */
1246             v9fs_path_copy(target, dir_path);
1247         } else if (!strcmp(name, "..")) {
1248             if (!strcmp(dir_path->data, ".")) {
1249                 /* ".." relative to the root is "." */
1250                 v9fs_path_sprintf(target, ".");
1251             } else {
1252                 char *tmp = g_path_get_dirname(dir_path->data);
1253                 /* Symbolic links are resolved by the client. We can assume
1254                  * that ".." relative to "foo/bar" is equivalent to "foo"
1255                  */
1256                 v9fs_path_sprintf(target, "%s", tmp);
1257                 g_free(tmp);
1258             }
1259         } else {
1260             assert(!strchr(name, '/'));
1261             v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
1262         }
1263     } else if (!strcmp(name, "/") || !strcmp(name, ".") ||
1264                !strcmp(name, "..")) {
1265             /* This is the root fid */
1266         v9fs_path_sprintf(target, ".");
1267     } else {
1268         assert(!strchr(name, '/'));
1269         v9fs_path_sprintf(target, "./%s", name);
1270     }
1271     return 0;
1272 }
1273
1274 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
1275                           const char *old_name, V9fsPath *newdir,
1276                           const char *new_name)
1277 {
1278     int ret;
1279     int odirfd, ndirfd;
1280
1281     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1282         (local_is_mapped_file_metadata(ctx, old_name) ||
1283          local_is_mapped_file_metadata(ctx, new_name))) {
1284         errno = EINVAL;
1285         return -1;
1286     }
1287
1288     odirfd = local_opendir_nofollow(ctx, olddir->data);
1289     if (odirfd == -1) {
1290         return -1;
1291     }
1292
1293     ndirfd = local_opendir_nofollow(ctx, newdir->data);
1294     if (ndirfd == -1) {
1295         close_preserve_errno(odirfd);
1296         return -1;
1297     }
1298
1299     ret = renameat(odirfd, old_name, ndirfd, new_name);
1300     if (ret < 0) {
1301         goto out;
1302     }
1303
1304     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1305         int omap_dirfd, nmap_dirfd;
1306
1307         ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
1308         if (ret < 0 && errno != EEXIST) {
1309             goto err_undo_rename;
1310         }
1311
1312         omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
1313         if (omap_dirfd == -1) {
1314             goto err;
1315         }
1316
1317         nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
1318         if (nmap_dirfd == -1) {
1319             close_preserve_errno(omap_dirfd);
1320             goto err;
1321         }
1322
1323         /* rename the .virtfs_metadata files */
1324         ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name);
1325         close_preserve_errno(nmap_dirfd);
1326         close_preserve_errno(omap_dirfd);
1327         if (ret < 0 && errno != ENOENT) {
1328             goto err_undo_rename;
1329         }
1330
1331         ret = 0;
1332     }
1333     goto out;
1334
1335 err:
1336     ret = -1;
1337 err_undo_rename:
1338     renameat_preserve_errno(ndirfd, new_name, odirfd, old_name);
1339 out:
1340     close_preserve_errno(ndirfd);
1341     close_preserve_errno(odirfd);
1342     return ret;
1343 }
1344
1345 static void v9fs_path_init_dirname(V9fsPath *path, const char *str)
1346 {
1347     path->data = g_path_get_dirname(str);
1348     path->size = strlen(path->data) + 1;
1349 }
1350
1351 static int local_rename(FsContext *ctx, const char *oldpath,
1352                         const char *newpath)
1353 {
1354     int err;
1355     char *oname = g_path_get_basename(oldpath);
1356     char *nname = g_path_get_basename(newpath);
1357     V9fsPath olddir, newdir;
1358
1359     v9fs_path_init_dirname(&olddir, oldpath);
1360     v9fs_path_init_dirname(&newdir, newpath);
1361
1362     err = local_renameat(ctx, &olddir, oname, &newdir, nname);
1363
1364     v9fs_path_free(&newdir);
1365     v9fs_path_free(&olddir);
1366     g_free(nname);
1367     g_free(oname);
1368
1369     return err;
1370 }
1371
1372 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
1373                           const char *name, int flags)
1374 {
1375     int ret;
1376     int dirfd;
1377
1378     if (ctx->export_flags & V9FS_SM_MAPPED_FILE &&
1379         local_is_mapped_file_metadata(ctx, name)) {
1380         errno = EINVAL;
1381         return -1;
1382     }
1383
1384     dirfd = local_opendir_nofollow(ctx, dir->data);
1385     if (dirfd == -1) {
1386         return -1;
1387     }
1388
1389     ret = local_unlinkat_common(ctx, dirfd, name, flags);
1390     close_preserve_errno(dirfd);
1391     return ret;
1392 }
1393
1394 #ifdef FS_IOC_GETVERSION
1395 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1396                                 mode_t st_mode, uint64_t *st_gen)
1397 {
1398     int err;
1399     V9fsFidOpenState fid_open;
1400
1401     /*
1402      * Do not try to open special files like device nodes, fifos etc
1403      * We can get fd for regular files and directories only
1404      */
1405     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1406         errno = ENOTTY;
1407         return -1;
1408     }
1409     err = local_open(ctx, path, O_RDONLY, &fid_open);
1410     if (err < 0) {
1411         return err;
1412     }
1413     err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1414     local_close(ctx, &fid_open);
1415     return err;
1416 }
1417 #endif
1418
1419 static int local_ioc_getversion_init(FsContext *ctx, LocalData *data, Error **errp)
1420 {
1421 #ifdef FS_IOC_GETVERSION
1422     struct statfs stbuf;
1423
1424     /*
1425      * use ioc_getversion only if the ioctl is definied
1426      */
1427     if (fstatfs(data->mountfd, &stbuf) < 0) {
1428         error_setg_errno(errp, errno,
1429                          "failed to stat file system at '%s'", ctx->fs_root);
1430         return -1;
1431     }
1432     switch (stbuf.f_type) {
1433     case EXT2_SUPER_MAGIC:
1434     case BTRFS_SUPER_MAGIC:
1435     case REISERFS_SUPER_MAGIC:
1436     case XFS_SUPER_MAGIC:
1437         ctx->exops.get_st_gen = local_ioc_getversion;
1438         break;
1439     }
1440 #endif
1441     return 0;
1442 }
1443
1444 static int local_init(FsContext *ctx, Error **errp)
1445 {
1446     LocalData *data = g_malloc(sizeof(*data));
1447
1448     data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
1449     if (data->mountfd == -1) {
1450         error_setg_errno(errp, errno, "failed to open '%s'", ctx->fs_root);
1451         goto err;
1452     }
1453
1454     if (local_ioc_getversion_init(ctx, data, errp) < 0) {
1455         close(data->mountfd);
1456         goto err;
1457     }
1458
1459     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1460         ctx->xops = passthrough_xattr_ops;
1461     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1462         ctx->xops = mapped_xattr_ops;
1463     } else if (ctx->export_flags & V9FS_SM_NONE) {
1464         ctx->xops = none_xattr_ops;
1465     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1466         /*
1467          * xattr operation for mapped-file and passthrough
1468          * remain same.
1469          */
1470         ctx->xops = passthrough_xattr_ops;
1471     }
1472     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1473
1474     ctx->private = data;
1475     return 0;
1476
1477 err:
1478     g_free(data);
1479     return -1;
1480 }
1481
1482 static void local_cleanup(FsContext *ctx)
1483 {
1484     LocalData *data = ctx->private;
1485
1486     if (!data) {
1487         return;
1488     }
1489
1490     close(data->mountfd);
1491     g_free(data);
1492 }
1493
1494 static void error_append_security_model_hint(Error *const *errp)
1495 {
1496     error_append_hint(errp, "Valid options are: security_model="
1497                       "[passthrough|mapped-xattr|mapped-file|none]\n");
1498 }
1499
1500 static int local_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
1501 {
1502     ERRP_GUARD();
1503     const char *sec_model = qemu_opt_get(opts, "security_model");
1504     const char *path = qemu_opt_get(opts, "path");
1505     const char *multidevs = qemu_opt_get(opts, "multidevs");
1506
1507     if (!sec_model) {
1508         error_setg(errp, "security_model property not set");
1509         error_append_security_model_hint(errp);
1510         return -1;
1511     }
1512
1513     if (!strcmp(sec_model, "passthrough")) {
1514         fse->export_flags |= V9FS_SM_PASSTHROUGH;
1515     } else if (!strcmp(sec_model, "mapped") ||
1516                !strcmp(sec_model, "mapped-xattr")) {
1517         fse->export_flags |= V9FS_SM_MAPPED;
1518     } else if (!strcmp(sec_model, "none")) {
1519         fse->export_flags |= V9FS_SM_NONE;
1520     } else if (!strcmp(sec_model, "mapped-file")) {
1521         fse->export_flags |= V9FS_SM_MAPPED_FILE;
1522     } else {
1523         error_setg(errp, "invalid security_model property '%s'", sec_model);
1524         error_append_security_model_hint(errp);
1525         return -1;
1526     }
1527
1528     if (multidevs) {
1529         if (!strcmp(multidevs, "remap")) {
1530             fse->export_flags &= ~V9FS_FORBID_MULTIDEVS;
1531             fse->export_flags |= V9FS_REMAP_INODES;
1532         } else if (!strcmp(multidevs, "forbid")) {
1533             fse->export_flags &= ~V9FS_REMAP_INODES;
1534             fse->export_flags |= V9FS_FORBID_MULTIDEVS;
1535         } else if (!strcmp(multidevs, "warn")) {
1536             fse->export_flags &= ~V9FS_FORBID_MULTIDEVS;
1537             fse->export_flags &= ~V9FS_REMAP_INODES;
1538         } else {
1539             error_setg(errp, "invalid multidevs property '%s'",
1540                        multidevs);
1541             error_append_hint(errp, "Valid options are: multidevs="
1542                               "[remap|forbid|warn]\n");
1543             return -1;
1544         }
1545     }
1546
1547     if (!path) {
1548         error_setg(errp, "path property not set");
1549         return -1;
1550     }
1551
1552     if (fsdev_throttle_parse_opts(opts, &fse->fst, errp)) {
1553         error_prepend(errp, "invalid throttle configuration: ");
1554         return -1;
1555     }
1556
1557     if (fse->export_flags & V9FS_SM_MAPPED ||
1558         fse->export_flags & V9FS_SM_MAPPED_FILE) {
1559         fse->fmode =
1560             qemu_opt_get_number(opts, "fmode", SM_LOCAL_MODE_BITS) & 0777;
1561         fse->dmode =
1562             qemu_opt_get_number(opts, "dmode", SM_LOCAL_DIR_MODE_BITS) & 0777;
1563     } else {
1564         if (qemu_opt_find(opts, "fmode")) {
1565             error_setg(errp, "fmode is only valid for mapped security modes");
1566             return -1;
1567         }
1568         if (qemu_opt_find(opts, "dmode")) {
1569             error_setg(errp, "dmode is only valid for mapped security modes");
1570             return -1;
1571         }
1572     }
1573
1574     fse->path = g_strdup(path);
1575
1576     return 0;
1577 }
1578
1579 FileOperations local_ops = {
1580     .parse_opts = local_parse_opts,
1581     .init  = local_init,
1582     .cleanup = local_cleanup,
1583     .lstat = local_lstat,
1584     .readlink = local_readlink,
1585     .close = local_close,
1586     .closedir = local_closedir,
1587     .open = local_open,
1588     .opendir = local_opendir,
1589     .rewinddir = local_rewinddir,
1590     .telldir = local_telldir,
1591     .readdir = local_readdir,
1592     .seekdir = local_seekdir,
1593     .preadv = local_preadv,
1594     .pwritev = local_pwritev,
1595     .chmod = local_chmod,
1596     .mknod = local_mknod,
1597     .mkdir = local_mkdir,
1598     .fstat = local_fstat,
1599     .open2 = local_open2,
1600     .symlink = local_symlink,
1601     .link = local_link,
1602     .truncate = local_truncate,
1603     .rename = local_rename,
1604     .chown = local_chown,
1605     .utimensat = local_utimensat,
1606     .remove = local_remove,
1607     .fsync = local_fsync,
1608     .statfs = local_statfs,
1609     .lgetxattr = local_lgetxattr,
1610     .llistxattr = local_llistxattr,
1611     .lsetxattr = local_lsetxattr,
1612     .lremovexattr = local_lremovexattr,
1613     .name_to_path = local_name_to_path,
1614     .renameat  = local_renameat,
1615     .unlinkat = local_unlinkat,
1616 };