hw/9pfs/virtio-9p-local.c

   1 /*
   2  * Virtio 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 "hw/virtio/virtio.h"
  15 #include "virtio-9p.h"
  16 #include "virtio-9p-xattr.h"
  17 #include <arpa/inet.h>
  18 #include <pwd.h>
  19 #include <grp.h>
  20 #include <sys/socket.h>
  21 #include <sys/un.h>
  22 #include "qemu/xattr.h"
  23 #include <libgen.h>
  24 #include <linux/fs.h>
  25 #ifdef CONFIG_LINUX_MAGIC_H
  26 #include <linux/magic.h>
  27 #endif
  28 #include <sys/ioctl.h>
  29
  30 #ifndef XFS_SUPER_MAGIC
  31 #define XFS_SUPER_MAGIC  0x58465342
  32 #endif
  33 #ifndef EXT2_SUPER_MAGIC
  34 #define EXT2_SUPER_MAGIC 0xEF53
  35 #endif
  36 #ifndef REISERFS_SUPER_MAGIC
  37 #define REISERFS_SUPER_MAGIC 0x52654973
  38 #endif
  39 #ifndef BTRFS_SUPER_MAGIC
  40 #define BTRFS_SUPER_MAGIC 0x9123683E
  41 #endif
  42
  43 #define VIRTFS_META_DIR ".virtfs_metadata"
  44
  45 static const char *local_mapped_attr_path(FsContext *ctx,
  46                                           const char *path, char *buffer)
  47 {
  48     char *dir_name;
  49     char *tmp_path = g_strdup(path);
  50     char *base_name = basename(tmp_path);
  51
  52     /* NULL terminate the directory */
  53     dir_name = tmp_path;
  54     *(base_name - 1) = '\0';
  55
  56     snprintf(buffer, PATH_MAX, "%s/%s/%s/%s",
  57              ctx->fs_root, dir_name, VIRTFS_META_DIR, base_name);
  58     g_free(tmp_path);
  59     return buffer;
  60 }
  61
  62 #define ATTR_MAX 100
  63 static void local_mapped_file_attr(FsContext *ctx, const char *path,
  64                                    struct stat *stbuf)
  65 {
  66     FILE *fp;
  67     char buf[ATTR_MAX];
  68     char attr_path[PATH_MAX];
  69
  70     local_mapped_attr_path(ctx, path, attr_path);
  71     fp = fopen(attr_path, "r");
  72     if (!fp) {
  73         return;
  74     }
  75     memset(buf, 0, ATTR_MAX);
  76     while (fgets(buf, ATTR_MAX, fp)) {
  77         if (!strncmp(buf, "virtfs.uid", 10)) {
  78             stbuf->st_uid = atoi(buf+11);
  79         } else if (!strncmp(buf, "virtfs.gid", 10)) {
  80             stbuf->st_gid = atoi(buf+11);
  81         } else if (!strncmp(buf, "virtfs.mode", 11)) {
  82             stbuf->st_mode = atoi(buf+12);
  83         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
  84             stbuf->st_rdev = atoi(buf+12);
  85         }
  86         memset(buf, 0, ATTR_MAX);
  87     }
  88     fclose(fp);
  89 }
  90
  91 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
  92 {
  93     int err;
  94     char buffer[PATH_MAX];
  95     char *path = fs_path->data;
  96
  97     err =  lstat(rpath(fs_ctx, path, buffer), stbuf);
  98     if (err) {
  99         return err;
 100     }
 101     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 102         /* Actual credentials are part of extended attrs */
 103         uid_t tmp_uid;
 104         gid_t tmp_gid;
 105         mode_t tmp_mode;
 106         dev_t tmp_dev;
 107         if (getxattr(rpath(fs_ctx, path, buffer), "user.virtfs.uid", &tmp_uid,
 108                     sizeof(uid_t)) > 0) {
 109             stbuf->st_uid = tmp_uid;
 110         }
 111         if (getxattr(rpath(fs_ctx, path, buffer), "user.virtfs.gid", &tmp_gid,
 112                     sizeof(gid_t)) > 0) {
 113             stbuf->st_gid = tmp_gid;
 114         }
 115         if (getxattr(rpath(fs_ctx, path, buffer), "user.virtfs.mode",
 116                     &tmp_mode, sizeof(mode_t)) > 0) {
 117             stbuf->st_mode = tmp_mode;
 118         }
 119         if (getxattr(rpath(fs_ctx, path, buffer), "user.virtfs.rdev", &tmp_dev,
 120                         sizeof(dev_t)) > 0) {
 121                 stbuf->st_rdev = tmp_dev;
 122         }
 123     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 124         local_mapped_file_attr(fs_ctx, path, stbuf);
 125     }
 126     return err;
 127 }
 128
 129 static int local_create_mapped_attr_dir(FsContext *ctx, const char *path)
 130 {
 131     int err;
 132     char attr_dir[PATH_MAX];
 133     char *tmp_path = g_strdup(path);
 134
 135     snprintf(attr_dir, PATH_MAX, "%s/%s/%s",
 136              ctx->fs_root, dirname(tmp_path), VIRTFS_META_DIR);
 137
 138     err = mkdir(attr_dir, 0700);
 139     if (err < 0 && errno == EEXIST) {
 140         err = 0;
 141     }
 142     g_free(tmp_path);
 143     return err;
 144 }
 145
 146 static int local_set_mapped_file_attr(FsContext *ctx,
 147                                       const char *path, FsCred *credp)
 148 {
 149     FILE *fp;
 150     int ret = 0;
 151     char buf[ATTR_MAX];
 152     char attr_path[PATH_MAX];
 153     int uid = -1, gid = -1, mode = -1, rdev = -1;
 154
 155     fp = fopen(local_mapped_attr_path(ctx, path, attr_path), "r");
 156     if (!fp) {
 157         goto create_map_file;
 158     }
 159     memset(buf, 0, ATTR_MAX);
 160     while (fgets(buf, ATTR_MAX, fp)) {
 161         if (!strncmp(buf, "virtfs.uid", 10)) {
 162             uid = atoi(buf+11);
 163         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 164             gid = atoi(buf+11);
 165         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 166             mode = atoi(buf+12);
 167         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 168             rdev = atoi(buf+12);
 169         }
 170         memset(buf, 0, ATTR_MAX);
 171     }
 172     fclose(fp);
 173     goto update_map_file;
 174
 175 create_map_file:
 176     ret = local_create_mapped_attr_dir(ctx, path);
 177     if (ret < 0) {
 178         goto err_out;
 179     }
 180
 181 update_map_file:
 182     fp = fopen(attr_path, "w");
 183     if (!fp) {
 184         ret = -1;
 185         goto err_out;
 186     }
 187
 188     if (credp->fc_uid != -1) {
 189         uid = credp->fc_uid;
 190     }
 191     if (credp->fc_gid != -1) {
 192         gid = credp->fc_gid;
 193     }
 194     if (credp->fc_mode != -1) {
 195         mode = credp->fc_mode;
 196     }
 197     if (credp->fc_rdev != -1) {
 198         rdev = credp->fc_rdev;
 199     }
 200
 201
 202     if (uid != -1) {
 203         fprintf(fp, "virtfs.uid=%d\n", uid);
 204     }
 205     if (gid != -1) {
 206         fprintf(fp, "virtfs.gid=%d\n", gid);
 207     }
 208     if (mode != -1) {
 209         fprintf(fp, "virtfs.mode=%d\n", mode);
 210     }
 211     if (rdev != -1) {
 212         fprintf(fp, "virtfs.rdev=%d\n", rdev);
 213     }
 214     fclose(fp);
 215
 216 err_out:
 217     return ret;
 218 }
 219
 220 static int local_set_xattr(const char *path, FsCred *credp)
 221 {
 222     int err;
 223
 224     if (credp->fc_uid != -1) {
 225         err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),
 226                 0);
 227         if (err) {
 228             return err;
 229         }
 230     }
 231     if (credp->fc_gid != -1) {
 232         err = setxattr(path, "user.virtfs.gid", &credp->fc_gid, sizeof(gid_t),
 233                 0);
 234         if (err) {
 235             return err;
 236         }
 237     }
 238     if (credp->fc_mode != -1) {
 239         err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,
 240                 sizeof(mode_t), 0);
 241         if (err) {
 242             return err;
 243         }
 244     }
 245     if (credp->fc_rdev != -1) {
 246         err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,
 247                 sizeof(dev_t), 0);
 248         if (err) {
 249             return err;
 250         }
 251     }
 252     return 0;
 253 }
 254
 255 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
 256                                          FsCred *credp)
 257 {
 258     char buffer[PATH_MAX];
 259
 260     if (lchown(rpath(fs_ctx, path, buffer), credp->fc_uid,
 261                 credp->fc_gid) < 0) {
 262         /*
 263          * If we fail to change ownership and if we are
 264          * using security model none. Ignore the error
 265          */
 266         if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 267             return -1;
 268         }
 269     }
 270
 271     if (chmod(rpath(fs_ctx, path, buffer), credp->fc_mode & 07777) < 0) {
 272         return -1;
 273     }
 274     return 0;
 275 }
 276
 277 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
 278                               char *buf, size_t bufsz)
 279 {
 280     ssize_t tsize = -1;
 281     char buffer[PATH_MAX];
 282     char *path = fs_path->data;
 283
 284     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
 285         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 286         int fd;
 287         fd = open(rpath(fs_ctx, path, buffer), O_RDONLY | O_NOFOLLOW);
 288         if (fd == -1) {
 289             return -1;
 290         }
 291         do {
 292             tsize = read(fd, (void *)buf, bufsz);
 293         } while (tsize == -1 && errno == EINTR);
 294         close(fd);
 295         return tsize;
 296     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 297                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 298         tsize = readlink(rpath(fs_ctx, path, buffer), buf, bufsz);
 299     }
 300     return tsize;
 301 }
 302
 303 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
 304 {
 305     return close(fs->fd);
 306 }
 307
 308 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 309 {
 310     return closedir(fs->dir);
 311 }
 312
 313 static int local_open(FsContext *ctx, V9fsPath *fs_path,
 314                       int flags, V9fsFidOpenState *fs)
 315 {
 316     char buffer[PATH_MAX];
 317     char *path = fs_path->data;
 318
 319     fs->fd = open(rpath(ctx, path, buffer), flags);
 320     return fs->fd;
 321 }
 322
 323 static int local_opendir(FsContext *ctx,
 324                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 325 {
 326     char buffer[PATH_MAX];
 327     char *path = fs_path->data;
 328
 329     fs->dir = opendir(rpath(ctx, path, buffer));
 330     if (!fs->dir) {
 331         return -1;
 332     }
 333     return 0;
 334 }
 335
 336 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 337 {
 338     return rewinddir(fs->dir);
 339 }
 340
 341 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 342 {
 343     return telldir(fs->dir);
 344 }
 345
 346 static int local_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
 347                            struct dirent *entry,
 348                            struct dirent **result)
 349 {
 350     int ret;
 351
 352 again:
 353     ret = readdir_r(fs->dir, entry, result);
 354     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 355         if (!ret && *result != NULL &&
 356             !strcmp(entry->d_name, VIRTFS_META_DIR)) {
 357             /* skp the meta data directory */
 358             goto again;
 359         }
 360     }
 361     return ret;
 362 }
 363
 364 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 365 {
 366     return seekdir(fs->dir, off);
 367 }
 368
 369 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
 370                             const struct iovec *iov,
 371                             int iovcnt, off_t offset)
 372 {
 373 #ifdef CONFIG_PREADV
 374     return preadv(fs->fd, iov, iovcnt, offset);
 375 #else
 376     int err = lseek(fs->fd, offset, SEEK_SET);
 377     if (err == -1) {
 378         return err;
 379     } else {
 380         return readv(fs->fd, iov, iovcnt);
 381     }
 382 #endif
 383 }
 384
 385 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 386                              const struct iovec *iov,
 387                              int iovcnt, off_t offset)
 388 {
 389     ssize_t ret
 390 ;
 391 #ifdef CONFIG_PREADV
 392     ret = pwritev(fs->fd, iov, iovcnt, offset);
 393 #else
 394     int err = lseek(fs->fd, offset, SEEK_SET);
 395     if (err == -1) {
 396         return err;
 397     } else {
 398         ret = writev(fs->fd, iov, iovcnt);
 399     }
 400 #endif
 401 #ifdef CONFIG_SYNC_FILE_RANGE
 402     if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
 403         /*
 404          * Initiate a writeback. This is not a data integrity sync.
 405          * We want to ensure that we don't leave dirty pages in the cache
 406          * after write when writeout=immediate is sepcified.
 407          */
 408         sync_file_range(fs->fd, offset, ret,
 409                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
 410     }
 411 #endif
 412     return ret;
 413 }
 414
 415 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 416 {
 417     char buffer[PATH_MAX];
 418     char *path = fs_path->data;
 419
 420     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 421         return local_set_xattr(rpath(fs_ctx, path, buffer), credp);
 422     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 423         return local_set_mapped_file_attr(fs_ctx, path, credp);
 424     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 425                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 426         return chmod(rpath(fs_ctx, path, buffer), credp->fc_mode);
 427     }
 428     return -1;
 429 }
 430
 431 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
 432                        const char *name, FsCred *credp)
 433 {
 434     char *path;
 435     int err = -1;
 436     int serrno = 0;
 437     V9fsString fullname;
 438     char buffer[PATH_MAX];
 439
 440     v9fs_string_init(&fullname);
 441     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 442     path = fullname.data;
 443
 444     /* Determine the security model */
 445     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 446         err = mknod(rpath(fs_ctx, path, buffer),
 447                 SM_LOCAL_MODE_BITS|S_IFREG, 0);
 448         if (err == -1) {
 449             goto out;
 450         }
 451         err = local_set_xattr(rpath(fs_ctx, path, buffer), credp);
 452         if (err == -1) {
 453             serrno = errno;
 454             goto err_end;
 455         }
 456     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 457
 458         err = mknod(rpath(fs_ctx, path, buffer),
 459                     SM_LOCAL_MODE_BITS|S_IFREG, 0);
 460         if (err == -1) {
 461             goto out;
 462         }
 463         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 464         if (err == -1) {
 465             serrno = errno;
 466             goto err_end;
 467         }
 468     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 469                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 470         err = mknod(rpath(fs_ctx, path, buffer), credp->fc_mode,
 471                 credp->fc_rdev);
 472         if (err == -1) {
 473             goto out;
 474         }
 475         err = local_post_create_passthrough(fs_ctx, path, credp);
 476         if (err == -1) {
 477             serrno = errno;
 478             goto err_end;
 479         }
 480     }
 481     goto out;
 482
 483 err_end:
 484     remove(rpath(fs_ctx, path, buffer));
 485     errno = serrno;
 486 out:
 487     v9fs_string_free(&fullname);
 488     return err;
 489 }
 490
 491 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
 492                        const char *name, FsCred *credp)
 493 {
 494     char *path;
 495     int err = -1;
 496     int serrno = 0;
 497     V9fsString fullname;
 498     char buffer[PATH_MAX];
 499
 500     v9fs_string_init(&fullname);
 501     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 502     path = fullname.data;
 503
 504     /* Determine the security model */
 505     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 506         err = mkdir(rpath(fs_ctx, path, buffer), SM_LOCAL_DIR_MODE_BITS);
 507         if (err == -1) {
 508             goto out;
 509         }
 510         credp->fc_mode = credp->fc_mode|S_IFDIR;
 511         err = local_set_xattr(rpath(fs_ctx, path, buffer), credp);
 512         if (err == -1) {
 513             serrno = errno;
 514             goto err_end;
 515         }
 516     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 517         err = mkdir(rpath(fs_ctx, path, buffer), SM_LOCAL_DIR_MODE_BITS);
 518         if (err == -1) {
 519             goto out;
 520         }
 521         credp->fc_mode = credp->fc_mode|S_IFDIR;
 522         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 523         if (err == -1) {
 524             serrno = errno;
 525             goto err_end;
 526         }
 527     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 528                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 529         err = mkdir(rpath(fs_ctx, path, buffer), credp->fc_mode);
 530         if (err == -1) {
 531             goto out;
 532         }
 533         err = local_post_create_passthrough(fs_ctx, path, credp);
 534         if (err == -1) {
 535             serrno = errno;
 536             goto err_end;
 537         }
 538     }
 539     goto out;
 540
 541 err_end:
 542     remove(rpath(fs_ctx, path, buffer));
 543     errno = serrno;
 544 out:
 545     v9fs_string_free(&fullname);
 546     return err;
 547 }
 548
 549 static int local_fstat(FsContext *fs_ctx, int fid_type,
 550                        V9fsFidOpenState *fs, struct stat *stbuf)
 551 {
 552     int err, fd;
 553
 554     if (fid_type == P9_FID_DIR) {
 555         fd = dirfd(fs->dir);
 556     } else {
 557         fd = fs->fd;
 558     }
 559
 560     err = fstat(fd, stbuf);
 561     if (err) {
 562         return err;
 563     }
 564     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 565         /* Actual credentials are part of extended attrs */
 566         uid_t tmp_uid;
 567         gid_t tmp_gid;
 568         mode_t tmp_mode;
 569         dev_t tmp_dev;
 570
 571         if (fgetxattr(fd, "user.virtfs.uid",
 572                       &tmp_uid, sizeof(uid_t)) > 0) {
 573             stbuf->st_uid = tmp_uid;
 574         }
 575         if (fgetxattr(fd, "user.virtfs.gid",
 576                       &tmp_gid, sizeof(gid_t)) > 0) {
 577             stbuf->st_gid = tmp_gid;
 578         }
 579         if (fgetxattr(fd, "user.virtfs.mode",
 580                       &tmp_mode, sizeof(mode_t)) > 0) {
 581             stbuf->st_mode = tmp_mode;
 582         }
 583         if (fgetxattr(fd, "user.virtfs.rdev",
 584                       &tmp_dev, sizeof(dev_t)) > 0) {
 585                 stbuf->st_rdev = tmp_dev;
 586         }
 587     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 588         errno = EOPNOTSUPP;
 589         return -1;
 590     }
 591     return err;
 592 }
 593
 594 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
 595                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 596 {
 597     char *path;
 598     int fd = -1;
 599     int err = -1;
 600     int serrno = 0;
 601     V9fsString fullname;
 602     char buffer[PATH_MAX];
 603
 604     v9fs_string_init(&fullname);
 605     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 606     path = fullname.data;
 607
 608     /* Determine the security model */
 609     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 610         fd = open(rpath(fs_ctx, path, buffer), flags, SM_LOCAL_MODE_BITS);
 611         if (fd == -1) {
 612             err = fd;
 613             goto out;
 614         }
 615         credp->fc_mode = credp->fc_mode|S_IFREG;
 616         /* Set cleint credentials in xattr */
 617         err = local_set_xattr(rpath(fs_ctx, path, buffer), credp);
 618         if (err == -1) {
 619             serrno = errno;
 620             goto err_end;
 621         }
 622     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 623         fd = open(rpath(fs_ctx, path, buffer), flags, SM_LOCAL_MODE_BITS);
 624         if (fd == -1) {
 625             err = fd;
 626             goto out;
 627         }
 628         credp->fc_mode = credp->fc_mode|S_IFREG;
 629         /* Set client credentials in .virtfs_metadata directory files */
 630         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 631         if (err == -1) {
 632             serrno = errno;
 633             goto err_end;
 634         }
 635     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 636                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 637         fd = open(rpath(fs_ctx, path, buffer), flags, credp->fc_mode);
 638         if (fd == -1) {
 639             err = fd;
 640             goto out;
 641         }
 642         err = local_post_create_passthrough(fs_ctx, path, credp);
 643         if (err == -1) {
 644             serrno = errno;
 645             goto err_end;
 646         }
 647     }
 648     err = fd;
 649     fs->fd = fd;
 650     goto out;
 651
 652 err_end:
 653     close(fd);
 654     remove(rpath(fs_ctx, path, buffer));
 655     errno = serrno;
 656 out:
 657     v9fs_string_free(&fullname);
 658     return err;
 659 }
 660
 661
 662 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 663                          V9fsPath *dir_path, const char *name, FsCred *credp)
 664 {
 665     int err = -1;
 666     int serrno = 0;
 667     char *newpath;
 668     V9fsString fullname;
 669     char buffer[PATH_MAX];
 670
 671     v9fs_string_init(&fullname);
 672     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 673     newpath = fullname.data;
 674
 675     /* Determine the security model */
 676     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 677         int fd;
 678         ssize_t oldpath_size, write_size;
 679         fd = open(rpath(fs_ctx, newpath, buffer), O_CREAT|O_EXCL|O_RDWR,
 680                 SM_LOCAL_MODE_BITS);
 681         if (fd == -1) {
 682             err = fd;
 683             goto out;
 684         }
 685         /* Write the oldpath (target) to the file. */
 686         oldpath_size = strlen(oldpath);
 687         do {
 688             write_size = write(fd, (void *)oldpath, oldpath_size);
 689         } while (write_size == -1 && errno == EINTR);
 690
 691         if (write_size != oldpath_size) {
 692             serrno = errno;
 693             close(fd);
 694             err = -1;
 695             goto err_end;
 696         }
 697         close(fd);
 698         /* Set cleint credentials in symlink's xattr */
 699         credp->fc_mode = credp->fc_mode|S_IFLNK;
 700         err = local_set_xattr(rpath(fs_ctx, newpath, buffer), credp);
 701         if (err == -1) {
 702             serrno = errno;
 703             goto err_end;
 704         }
 705     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 706         int fd;
 707         ssize_t oldpath_size, write_size;
 708         fd = open(rpath(fs_ctx, newpath, buffer), O_CREAT|O_EXCL|O_RDWR,
 709                   SM_LOCAL_MODE_BITS);
 710         if (fd == -1) {
 711             err = fd;
 712             goto out;
 713         }
 714         /* Write the oldpath (target) to the file. */
 715         oldpath_size = strlen(oldpath);
 716         do {
 717             write_size = write(fd, (void *)oldpath, oldpath_size);
 718         } while (write_size == -1 && errno == EINTR);
 719
 720         if (write_size != oldpath_size) {
 721             serrno = errno;
 722             close(fd);
 723             err = -1;
 724             goto err_end;
 725         }
 726         close(fd);
 727         /* Set cleint credentials in symlink's xattr */
 728         credp->fc_mode = credp->fc_mode|S_IFLNK;
 729         err = local_set_mapped_file_attr(fs_ctx, newpath, credp);
 730         if (err == -1) {
 731             serrno = errno;
 732             goto err_end;
 733         }
 734     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 735                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 736         err = symlink(oldpath, rpath(fs_ctx, newpath, buffer));
 737         if (err) {
 738             goto out;
 739         }
 740         err = lchown(rpath(fs_ctx, newpath, buffer), credp->fc_uid,
 741                      credp->fc_gid);
 742         if (err == -1) {
 743             /*
 744              * If we fail to change ownership and if we are
 745              * using security model none. Ignore the error
 746              */
 747             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 748                 serrno = errno;
 749                 goto err_end;
 750             } else
 751                 err = 0;
 752         }
 753     }
 754     goto out;
 755
 756 err_end:
 757     remove(rpath(fs_ctx, newpath, buffer));
 758     errno = serrno;
 759 out:
 760     v9fs_string_free(&fullname);
 761     return err;
 762 }
 763
 764 static int local_link(FsContext *ctx, V9fsPath *oldpath,
 765                       V9fsPath *dirpath, const char *name)
 766 {
 767     int ret;
 768     V9fsString newpath;
 769     char buffer[PATH_MAX], buffer1[PATH_MAX];
 770
 771     v9fs_string_init(&newpath);
 772     v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
 773
 774     ret = link(rpath(ctx, oldpath->data, buffer),
 775                rpath(ctx, newpath.data, buffer1));
 776
 777     /* now link the virtfs_metadata files */
 778     if (!ret && (ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 779         /* Link the .virtfs_metadata files. Create the metada directory */
 780         ret = local_create_mapped_attr_dir(ctx, newpath.data);
 781         if (ret < 0) {
 782             goto err_out;
 783         }
 784         ret = link(local_mapped_attr_path(ctx, oldpath->data, buffer),
 785                    local_mapped_attr_path(ctx, newpath.data, buffer1));
 786         if (ret < 0 && errno != ENOENT) {
 787             goto err_out;
 788         }
 789     }
 790 err_out:
 791     v9fs_string_free(&newpath);
 792     return ret;
 793 }
 794
 795 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
 796 {
 797     char buffer[PATH_MAX];
 798     char *path = fs_path->data;
 799
 800     return truncate(rpath(ctx, path, buffer), size);
 801 }
 802
 803 static int local_rename(FsContext *ctx, const char *oldpath,
 804                         const char *newpath)
 805 {
 806     int err;
 807     char buffer[PATH_MAX], buffer1[PATH_MAX];
 808
 809     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 810         err = local_create_mapped_attr_dir(ctx, newpath);
 811         if (err < 0) {
 812             return err;
 813         }
 814         /* rename the .virtfs_metadata files */
 815         err = rename(local_mapped_attr_path(ctx, oldpath, buffer),
 816                      local_mapped_attr_path(ctx, newpath, buffer1));
 817         if (err < 0 && errno != ENOENT) {
 818             return err;
 819         }
 820     }
 821     return rename(rpath(ctx, oldpath, buffer), rpath(ctx, newpath, buffer1));
 822 }
 823
 824 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 825 {
 826     char buffer[PATH_MAX];
 827     char *path = fs_path->data;
 828
 829     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
 830         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 831         (fs_ctx->export_flags & V9FS_SM_NONE)) {
 832         return lchown(rpath(fs_ctx, path, buffer),
 833                       credp->fc_uid, credp->fc_gid);
 834     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 835         return local_set_xattr(rpath(fs_ctx, path, buffer), credp);
 836     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 837         return local_set_mapped_file_attr(fs_ctx, path, credp);
 838     }
 839     return -1;
 840 }
 841
 842 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
 843                            const struct timespec *buf)
 844 {
 845     char buffer[PATH_MAX];
 846     char *path = fs_path->data;
 847
 848     return qemu_utimens(rpath(s, path, buffer), buf);
 849 }
 850
 851 static int local_remove(FsContext *ctx, const char *path)
 852 {
 853     int err;
 854     struct stat stbuf;
 855     char buffer[PATH_MAX];
 856
 857     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 858         err =  lstat(rpath(ctx, path, buffer), &stbuf);
 859         if (err) {
 860             goto err_out;
 861         }
 862         /*
 863          * If directory remove .virtfs_metadata contained in the
 864          * directory
 865          */
 866         if (S_ISDIR(stbuf.st_mode)) {
 867             sprintf(buffer, "%s/%s/%s", ctx->fs_root, path, VIRTFS_META_DIR);
 868             err = remove(buffer);
 869             if (err < 0 && errno != ENOENT) {
 870                 /*
 871                  * We didn't had the .virtfs_metadata file. May be file created
 872                  * in non-mapped mode ?. Ignore ENOENT.
 873                  */
 874                 goto err_out;
 875             }
 876         }
 877         /*
 878          * Now remove the name from parent directory
 879          * .virtfs_metadata directory
 880          */
 881         err = remove(local_mapped_attr_path(ctx, path, buffer));
 882         if (err < 0 && errno != ENOENT) {
 883             /*
 884              * We didn't had the .virtfs_metadata file. May be file created
 885              * in non-mapped mode ?. Ignore ENOENT.
 886              */
 887             goto err_out;
 888         }
 889     }
 890     return remove(rpath(ctx, path, buffer));
 891 err_out:
 892     return err;
 893 }
 894
 895 static int local_fsync(FsContext *ctx, int fid_type,
 896                        V9fsFidOpenState *fs, int datasync)
 897 {
 898     int fd;
 899
 900     if (fid_type == P9_FID_DIR) {
 901         fd = dirfd(fs->dir);
 902     } else {
 903         fd = fs->fd;
 904     }
 905
 906     if (datasync) {
 907         return qemu_fdatasync(fd);
 908     } else {
 909         return fsync(fd);
 910     }
 911 }
 912
 913 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
 914 {
 915     char buffer[PATH_MAX];
 916     char *path = fs_path->data;
 917
 918     return statfs(rpath(s, path, buffer), stbuf);
 919 }
 920
 921 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
 922                                const char *name, void *value, size_t size)
 923 {
 924     char *path = fs_path->data;
 925
 926     return v9fs_get_xattr(ctx, path, name, value, size);
 927 }
 928
 929 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
 930                                 void *value, size_t size)
 931 {
 932     char *path = fs_path->data;
 933
 934     return v9fs_list_xattr(ctx, path, value, size);
 935 }
 936
 937 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
 938                            void *value, size_t size, int flags)
 939 {
 940     char *path = fs_path->data;
 941
 942     return v9fs_set_xattr(ctx, path, name, value, size, flags);
 943 }
 944
 945 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
 946                               const char *name)
 947 {
 948     char *path = fs_path->data;
 949
 950     return v9fs_remove_xattr(ctx, path, name);
 951 }
 952
 953 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
 954                               const char *name, V9fsPath *target)
 955 {
 956     if (dir_path) {
 957         v9fs_string_sprintf((V9fsString *)target, "%s/%s",
 958                             dir_path->data, name);
 959     } else {
 960         v9fs_string_sprintf((V9fsString *)target, "%s", name);
 961     }
 962     /* Bump the size for including terminating NULL */
 963     target->size++;
 964     return 0;
 965 }
 966
 967 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
 968                           const char *old_name, V9fsPath *newdir,
 969                           const char *new_name)
 970 {
 971     int ret;
 972     V9fsString old_full_name, new_full_name;
 973
 974     v9fs_string_init(&old_full_name);
 975     v9fs_string_init(&new_full_name);
 976
 977     v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
 978     v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
 979
 980     ret = local_rename(ctx, old_full_name.data, new_full_name.data);
 981     v9fs_string_free(&old_full_name);
 982     v9fs_string_free(&new_full_name);
 983     return ret;
 984 }
 985
 986 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
 987                           const char *name, int flags)
 988 {
 989     int ret;
 990     V9fsString fullname;
 991     char buffer[PATH_MAX];
 992
 993     v9fs_string_init(&fullname);
 994
 995     v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
 996     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 997         if (flags == AT_REMOVEDIR) {
 998             /*
 999              * If directory remove .virtfs_metadata contained in the
1000              * directory
1001              */
1002             sprintf(buffer, "%s/%s/%s", ctx->fs_root,
1003                     fullname.data, VIRTFS_META_DIR);
1004             ret = remove(buffer);
1005             if (ret < 0 && errno != ENOENT) {
1006                 /*
1007                  * We didn't had the .virtfs_metadata file. May be file created
1008                  * in non-mapped mode ?. Ignore ENOENT.
1009                  */
1010                 goto err_out;
1011             }
1012         }
1013         /*
1014          * Now remove the name from parent directory
1015          * .virtfs_metadata directory.
1016          */
1017         ret = remove(local_mapped_attr_path(ctx, fullname.data, buffer));
1018         if (ret < 0 && errno != ENOENT) {
1019             /*
1020              * We didn't had the .virtfs_metadata file. May be file created
1021              * in non-mapped mode ?. Ignore ENOENT.
1022              */
1023             goto err_out;
1024         }
1025     }
1026     /* Remove the name finally */
1027     ret = remove(rpath(ctx, fullname.data, buffer));
1028     v9fs_string_free(&fullname);
1029
1030 err_out:
1031     return ret;
1032 }
1033
1034 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1035                                 mode_t st_mode, uint64_t *st_gen)
1036 {
1037     int err;
1038 #ifdef FS_IOC_GETVERSION
1039     V9fsFidOpenState fid_open;
1040
1041     /*
1042      * Do not try to open special files like device nodes, fifos etc
1043      * We can get fd for regular files and directories only
1044      */
1045     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1046             return 0;
1047     }
1048     err = local_open(ctx, path, O_RDONLY, &fid_open);
1049     if (err < 0) {
1050         return err;
1051     }
1052     err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1053     local_close(ctx, &fid_open);
1054 #else
1055     err = -ENOTTY;
1056 #endif
1057     return err;
1058 }
1059
1060 static int local_init(FsContext *ctx)
1061 {
1062     int err = 0;
1063     struct statfs stbuf;
1064
1065     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1066         ctx->xops = passthrough_xattr_ops;
1067     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1068         ctx->xops = mapped_xattr_ops;
1069     } else if (ctx->export_flags & V9FS_SM_NONE) {
1070         ctx->xops = none_xattr_ops;
1071     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1072         /*
1073          * xattr operation for mapped-file and passthrough
1074          * remain same.
1075          */
1076         ctx->xops = passthrough_xattr_ops;
1077     }
1078     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1079 #ifdef FS_IOC_GETVERSION
1080     /*
1081      * use ioc_getversion only if the iocl is definied
1082      */
1083     err = statfs(ctx->fs_root, &stbuf);
1084     if (!err) {
1085         switch (stbuf.f_type) {
1086         case EXT2_SUPER_MAGIC:
1087         case BTRFS_SUPER_MAGIC:
1088         case REISERFS_SUPER_MAGIC:
1089         case XFS_SUPER_MAGIC:
1090             ctx->exops.get_st_gen = local_ioc_getversion;
1091             break;
1092         }
1093     }
1094 #endif
1095     return err;
1096 }
1097
1098 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
1099 {
1100     const char *sec_model = qemu_opt_get(opts, "security_model");
1101     const char *path = qemu_opt_get(opts, "path");
1102
1103     if (!sec_model) {
1104         fprintf(stderr, "security model not specified, "
1105                 "local fs needs security model\nvalid options are:"
1106                 "\tsecurity_model=[passthrough|mapped|none]\n");
1107         return -1;
1108     }
1109
1110     if (!strcmp(sec_model, "passthrough")) {
1111         fse->export_flags |= V9FS_SM_PASSTHROUGH;
1112     } else if (!strcmp(sec_model, "mapped") ||
1113                !strcmp(sec_model, "mapped-xattr")) {
1114         fse->export_flags |= V9FS_SM_MAPPED;
1115     } else if (!strcmp(sec_model, "none")) {
1116         fse->export_flags |= V9FS_SM_NONE;
1117     } else if (!strcmp(sec_model, "mapped-file")) {
1118         fse->export_flags |= V9FS_SM_MAPPED_FILE;
1119     } else {
1120         fprintf(stderr, "Invalid security model %s specified, valid options are"
1121                 "\n\t [passthrough|mapped-xattr|mapped-file|none]\n",
1122                 sec_model);
1123         return -1;
1124     }
1125
1126     if (!path) {
1127         fprintf(stderr, "fsdev: No path specified.\n");
1128         return -1;
1129     }
1130     fse->path = g_strdup(path);
1131
1132     return 0;
1133 }
1134
1135 FileOperations local_ops = {
1136     .parse_opts = local_parse_opts,
1137     .init  = local_init,
1138     .lstat = local_lstat,
1139     .readlink = local_readlink,
1140     .close = local_close,
1141     .closedir = local_closedir,
1142     .open = local_open,
1143     .opendir = local_opendir,
1144     .rewinddir = local_rewinddir,
1145     .telldir = local_telldir,
1146     .readdir_r = local_readdir_r,
1147     .seekdir = local_seekdir,
1148     .preadv = local_preadv,
1149     .pwritev = local_pwritev,
1150     .chmod = local_chmod,
1151     .mknod = local_mknod,
1152     .mkdir = local_mkdir,
1153     .fstat = local_fstat,
1154     .open2 = local_open2,
1155     .symlink = local_symlink,
1156     .link = local_link,
1157     .truncate = local_truncate,
1158     .rename = local_rename,
1159     .chown = local_chown,
1160     .utimensat = local_utimensat,
1161     .remove = local_remove,
1162     .fsync = local_fsync,
1163     .statfs = local_statfs,
1164     .lgetxattr = local_lgetxattr,
1165     .llistxattr = local_llistxattr,
1166     .lsetxattr = local_lsetxattr,
1167     .lremovexattr = local_lremovexattr,
1168     .name_to_path = local_name_to_path,
1169     .renameat  = local_renameat,
1170     .unlinkat = local_unlinkat,
1171 };