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 char *local_mapped_attr_path(FsContext *ctx, const char *path)
  46 {
  47     char *dir_name;
  48     char *tmp_path = g_strdup(path);
  49     char *base_name = basename(tmp_path);
  50     char *buffer;
  51
  52     /* NULL terminate the directory */
  53     dir_name = tmp_path;
  54     *(base_name - 1) = '\0';
  55
  56     buffer = g_strdup_printf("%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 static FILE *local_fopen(const char *path, const char *mode)
  63 {
  64     int fd, o_mode = 0;
  65     FILE *fp;
  66     int flags = O_NOFOLLOW;
  67     /*
  68      * only supports two modes
  69      */
  70     if (mode[0] == 'r') {
  71         flags |= O_RDONLY;
  72     } else if (mode[0] == 'w') {
  73         flags |= O_WRONLY | O_TRUNC | O_CREAT;
  74         o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
  75     } else {
  76         return NULL;
  77     }
  78     fd = open(path, flags, o_mode);
  79     if (fd == -1) {
  80         return NULL;
  81     }
  82     fp = fdopen(fd, mode);
  83     if (!fp) {
  84         close(fd);
  85     }
  86     return fp;
  87 }
  88
  89 #define ATTR_MAX 100
  90 static void local_mapped_file_attr(FsContext *ctx, const char *path,
  91                                    struct stat *stbuf)
  92 {
  93     FILE *fp;
  94     char buf[ATTR_MAX];
  95     char *attr_path;
  96
  97     attr_path = local_mapped_attr_path(ctx, path);
  98     fp = local_fopen(attr_path, "r");
  99     g_free(attr_path);
 100     if (!fp) {
 101         return;
 102     }
 103     memset(buf, 0, ATTR_MAX);
 104     while (fgets(buf, ATTR_MAX, fp)) {
 105         if (!strncmp(buf, "virtfs.uid", 10)) {
 106             stbuf->st_uid = atoi(buf+11);
 107         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 108             stbuf->st_gid = atoi(buf+11);
 109         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 110             stbuf->st_mode = atoi(buf+12);
 111         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 112             stbuf->st_rdev = atoi(buf+12);
 113         }
 114         memset(buf, 0, ATTR_MAX);
 115     }
 116     fclose(fp);
 117 }
 118
 119 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
 120 {
 121     int err;
 122     char *buffer;
 123     char *path = fs_path->data;
 124
 125     buffer = rpath(fs_ctx, path);
 126     err =  lstat(buffer, stbuf);
 127     if (err) {
 128         goto err_out;
 129     }
 130     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 131         /* Actual credentials are part of extended attrs */
 132         uid_t tmp_uid;
 133         gid_t tmp_gid;
 134         mode_t tmp_mode;
 135         dev_t tmp_dev;
 136         if (getxattr(buffer, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
 137             stbuf->st_uid = tmp_uid;
 138         }
 139         if (getxattr(buffer, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
 140             stbuf->st_gid = tmp_gid;
 141         }
 142         if (getxattr(buffer, "user.virtfs.mode",
 143                     &tmp_mode, sizeof(mode_t)) > 0) {
 144             stbuf->st_mode = tmp_mode;
 145         }
 146         if (getxattr(buffer, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
 147                 stbuf->st_rdev = tmp_dev;
 148         }
 149     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 150         local_mapped_file_attr(fs_ctx, path, stbuf);
 151     }
 152
 153 err_out:
 154     g_free(buffer);
 155     return err;
 156 }
 157
 158 static int local_create_mapped_attr_dir(FsContext *ctx, const char *path)
 159 {
 160     int err;
 161     char *attr_dir;
 162     char *tmp_path = g_strdup(path);
 163
 164     attr_dir = g_strdup_printf("%s/%s/%s",
 165              ctx->fs_root, dirname(tmp_path), VIRTFS_META_DIR);
 166
 167     err = mkdir(attr_dir, 0700);
 168     if (err < 0 && errno == EEXIST) {
 169         err = 0;
 170     }
 171     g_free(attr_dir);
 172     g_free(tmp_path);
 173     return err;
 174 }
 175
 176 static int local_set_mapped_file_attr(FsContext *ctx,
 177                                       const char *path, FsCred *credp)
 178 {
 179     FILE *fp;
 180     int ret = 0;
 181     char buf[ATTR_MAX];
 182     char *attr_path;
 183     int uid = -1, gid = -1, mode = -1, rdev = -1;
 184
 185     attr_path = local_mapped_attr_path(ctx, path);
 186     fp = local_fopen(attr_path, "r");
 187     if (!fp) {
 188         goto create_map_file;
 189     }
 190     memset(buf, 0, ATTR_MAX);
 191     while (fgets(buf, ATTR_MAX, fp)) {
 192         if (!strncmp(buf, "virtfs.uid", 10)) {
 193             uid = atoi(buf+11);
 194         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 195             gid = atoi(buf+11);
 196         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 197             mode = atoi(buf+12);
 198         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 199             rdev = atoi(buf+12);
 200         }
 201         memset(buf, 0, ATTR_MAX);
 202     }
 203     fclose(fp);
 204     goto update_map_file;
 205
 206 create_map_file:
 207     ret = local_create_mapped_attr_dir(ctx, path);
 208     if (ret < 0) {
 209         goto err_out;
 210     }
 211
 212 update_map_file:
 213     fp = local_fopen(attr_path, "w");
 214     if (!fp) {
 215         ret = -1;
 216         goto err_out;
 217     }
 218
 219     if (credp->fc_uid != -1) {
 220         uid = credp->fc_uid;
 221     }
 222     if (credp->fc_gid != -1) {
 223         gid = credp->fc_gid;
 224     }
 225     if (credp->fc_mode != -1) {
 226         mode = credp->fc_mode;
 227     }
 228     if (credp->fc_rdev != -1) {
 229         rdev = credp->fc_rdev;
 230     }
 231
 232
 233     if (uid != -1) {
 234         fprintf(fp, "virtfs.uid=%d\n", uid);
 235     }
 236     if (gid != -1) {
 237         fprintf(fp, "virtfs.gid=%d\n", gid);
 238     }
 239     if (mode != -1) {
 240         fprintf(fp, "virtfs.mode=%d\n", mode);
 241     }
 242     if (rdev != -1) {
 243         fprintf(fp, "virtfs.rdev=%d\n", rdev);
 244     }
 245     fclose(fp);
 246
 247 err_out:
 248     g_free(attr_path);
 249     return ret;
 250 }
 251
 252 static int local_set_xattr(const char *path, FsCred *credp)
 253 {
 254     int err;
 255
 256     if (credp->fc_uid != -1) {
 257         err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),
 258                 0);
 259         if (err) {
 260             return err;
 261         }
 262     }
 263     if (credp->fc_gid != -1) {
 264         err = setxattr(path, "user.virtfs.gid", &credp->fc_gid, sizeof(gid_t),
 265                 0);
 266         if (err) {
 267             return err;
 268         }
 269     }
 270     if (credp->fc_mode != -1) {
 271         err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,
 272                 sizeof(mode_t), 0);
 273         if (err) {
 274             return err;
 275         }
 276     }
 277     if (credp->fc_rdev != -1) {
 278         err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,
 279                 sizeof(dev_t), 0);
 280         if (err) {
 281             return err;
 282         }
 283     }
 284     return 0;
 285 }
 286
 287 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
 288                                          FsCred *credp)
 289 {
 290     char *buffer;
 291
 292     buffer = rpath(fs_ctx, path);
 293     if (lchown(buffer, credp->fc_uid, credp->fc_gid) < 0) {
 294         /*
 295          * If we fail to change ownership and if we are
 296          * using security model none. Ignore the error
 297          */
 298         if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 299             goto err;
 300         }
 301     }
 302
 303     if (chmod(buffer, credp->fc_mode & 07777) < 0) {
 304         goto err;
 305     }
 306
 307     g_free(buffer);
 308     return 0;
 309 err:
 310     g_free(buffer);
 311     return -1;
 312 }
 313
 314 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
 315                               char *buf, size_t bufsz)
 316 {
 317     ssize_t tsize = -1;
 318     char *buffer;
 319     char *path = fs_path->data;
 320
 321     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
 322         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 323         int fd;
 324         buffer = rpath(fs_ctx, path);
 325         fd = open(buffer, O_RDONLY | O_NOFOLLOW);
 326         g_free(buffer);
 327         if (fd == -1) {
 328             return -1;
 329         }
 330         do {
 331             tsize = read(fd, (void *)buf, bufsz);
 332         } while (tsize == -1 && errno == EINTR);
 333         close(fd);
 334         return tsize;
 335     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 336                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 337         buffer = rpath(fs_ctx, path);
 338         tsize = readlink(buffer, buf, bufsz);
 339         g_free(buffer);
 340     }
 341     return tsize;
 342 }
 343
 344 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
 345 {
 346     return close(fs->fd);
 347 }
 348
 349 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 350 {
 351     return closedir(fs->dir);
 352 }
 353
 354 static int local_open(FsContext *ctx, V9fsPath *fs_path,
 355                       int flags, V9fsFidOpenState *fs)
 356 {
 357     char *buffer;
 358     char *path = fs_path->data;
 359
 360     buffer = rpath(ctx, path);
 361     fs->fd = open(buffer, flags | O_NOFOLLOW);
 362     g_free(buffer);
 363     return fs->fd;
 364 }
 365
 366 static int local_opendir(FsContext *ctx,
 367                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 368 {
 369     char *buffer;
 370     char *path = fs_path->data;
 371
 372     buffer = rpath(ctx, path);
 373     fs->dir = opendir(buffer);
 374     g_free(buffer);
 375     if (!fs->dir) {
 376         return -1;
 377     }
 378     return 0;
 379 }
 380
 381 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 382 {
 383     return rewinddir(fs->dir);
 384 }
 385
 386 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 387 {
 388     return telldir(fs->dir);
 389 }
 390
 391 static int local_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
 392                            struct dirent *entry,
 393                            struct dirent **result)
 394 {
 395     int ret;
 396
 397 again:
 398     ret = readdir_r(fs->dir, entry, result);
 399     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 400         if (!ret && *result != NULL &&
 401             !strcmp(entry->d_name, VIRTFS_META_DIR)) {
 402             /* skp the meta data directory */
 403             goto again;
 404         }
 405     }
 406     return ret;
 407 }
 408
 409 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 410 {
 411     return seekdir(fs->dir, off);
 412 }
 413
 414 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
 415                             const struct iovec *iov,
 416                             int iovcnt, off_t offset)
 417 {
 418 #ifdef CONFIG_PREADV
 419     return preadv(fs->fd, iov, iovcnt, offset);
 420 #else
 421     int err = lseek(fs->fd, offset, SEEK_SET);
 422     if (err == -1) {
 423         return err;
 424     } else {
 425         return readv(fs->fd, iov, iovcnt);
 426     }
 427 #endif
 428 }
 429
 430 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 431                              const struct iovec *iov,
 432                              int iovcnt, off_t offset)
 433 {
 434     ssize_t ret
 435 ;
 436 #ifdef CONFIG_PREADV
 437     ret = pwritev(fs->fd, iov, iovcnt, offset);
 438 #else
 439     int err = lseek(fs->fd, offset, SEEK_SET);
 440     if (err == -1) {
 441         return err;
 442     } else {
 443         ret = writev(fs->fd, iov, iovcnt);
 444     }
 445 #endif
 446 #ifdef CONFIG_SYNC_FILE_RANGE
 447     if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
 448         /*
 449          * Initiate a writeback. This is not a data integrity sync.
 450          * We want to ensure that we don't leave dirty pages in the cache
 451          * after write when writeout=immediate is sepcified.
 452          */
 453         sync_file_range(fs->fd, offset, ret,
 454                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
 455     }
 456 #endif
 457     return ret;
 458 }
 459
 460 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 461 {
 462     char *buffer;
 463     int ret = -1;
 464     char *path = fs_path->data;
 465
 466     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 467         buffer = rpath(fs_ctx, path);
 468         ret = local_set_xattr(buffer, credp);
 469         g_free(buffer);
 470     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 471         return local_set_mapped_file_attr(fs_ctx, path, credp);
 472     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 473                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 474         buffer = rpath(fs_ctx, path);
 475         ret = chmod(buffer, credp->fc_mode);
 476         g_free(buffer);
 477     }
 478     return ret;
 479 }
 480
 481 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
 482                        const char *name, FsCred *credp)
 483 {
 484     char *path;
 485     int err = -1;
 486     int serrno = 0;
 487     V9fsString fullname;
 488     char *buffer;
 489
 490     v9fs_string_init(&fullname);
 491     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 492     path = fullname.data;
 493
 494     /* Determine the security model */
 495     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 496         buffer = rpath(fs_ctx, path);
 497         err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
 498         if (err == -1) {
 499             g_free(buffer);
 500             goto out;
 501         }
 502         err = local_set_xattr(buffer, credp);
 503         if (err == -1) {
 504             serrno = errno;
 505             goto err_end;
 506         }
 507     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 508
 509         buffer = rpath(fs_ctx, path);
 510         err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
 511         if (err == -1) {
 512             g_free(buffer);
 513             goto out;
 514         }
 515         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 516         if (err == -1) {
 517             serrno = errno;
 518             goto err_end;
 519         }
 520     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 521                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 522         buffer = rpath(fs_ctx, path);
 523         err = mknod(buffer, credp->fc_mode, credp->fc_rdev);
 524         if (err == -1) {
 525             g_free(buffer);
 526             goto out;
 527         }
 528         err = local_post_create_passthrough(fs_ctx, path, credp);
 529         if (err == -1) {
 530             serrno = errno;
 531             goto err_end;
 532         }
 533     }
 534     goto out;
 535
 536 err_end:
 537     remove(buffer);
 538     errno = serrno;
 539     g_free(buffer);
 540 out:
 541     v9fs_string_free(&fullname);
 542     return err;
 543 }
 544
 545 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
 546                        const char *name, FsCred *credp)
 547 {
 548     char *path;
 549     int err = -1;
 550     int serrno = 0;
 551     V9fsString fullname;
 552     char *buffer;
 553
 554     v9fs_string_init(&fullname);
 555     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 556     path = fullname.data;
 557
 558     /* Determine the security model */
 559     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 560         buffer = rpath(fs_ctx, path);
 561         err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
 562         if (err == -1) {
 563             g_free(buffer);
 564             goto out;
 565         }
 566         credp->fc_mode = credp->fc_mode|S_IFDIR;
 567         err = local_set_xattr(buffer, credp);
 568         if (err == -1) {
 569             serrno = errno;
 570             goto err_end;
 571         }
 572     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 573         buffer = rpath(fs_ctx, path);
 574         err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
 575         if (err == -1) {
 576             g_free(buffer);
 577             goto out;
 578         }
 579         credp->fc_mode = credp->fc_mode|S_IFDIR;
 580         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 581         if (err == -1) {
 582             serrno = errno;
 583             goto err_end;
 584         }
 585     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 586                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 587         buffer = rpath(fs_ctx, path);
 588         err = mkdir(buffer, credp->fc_mode);
 589         if (err == -1) {
 590             g_free(buffer);
 591             goto out;
 592         }
 593         err = local_post_create_passthrough(fs_ctx, path, credp);
 594         if (err == -1) {
 595             serrno = errno;
 596             goto err_end;
 597         }
 598     }
 599     goto out;
 600
 601 err_end:
 602     remove(buffer);
 603     errno = serrno;
 604     g_free(buffer);
 605 out:
 606     v9fs_string_free(&fullname);
 607     return err;
 608 }
 609
 610 static int local_fstat(FsContext *fs_ctx, int fid_type,
 611                        V9fsFidOpenState *fs, struct stat *stbuf)
 612 {
 613     int err, fd;
 614
 615     if (fid_type == P9_FID_DIR) {
 616         fd = dirfd(fs->dir);
 617     } else {
 618         fd = fs->fd;
 619     }
 620
 621     err = fstat(fd, stbuf);
 622     if (err) {
 623         return err;
 624     }
 625     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 626         /* Actual credentials are part of extended attrs */
 627         uid_t tmp_uid;
 628         gid_t tmp_gid;
 629         mode_t tmp_mode;
 630         dev_t tmp_dev;
 631
 632         if (fgetxattr(fd, "user.virtfs.uid",
 633                       &tmp_uid, sizeof(uid_t)) > 0) {
 634             stbuf->st_uid = tmp_uid;
 635         }
 636         if (fgetxattr(fd, "user.virtfs.gid",
 637                       &tmp_gid, sizeof(gid_t)) > 0) {
 638             stbuf->st_gid = tmp_gid;
 639         }
 640         if (fgetxattr(fd, "user.virtfs.mode",
 641                       &tmp_mode, sizeof(mode_t)) > 0) {
 642             stbuf->st_mode = tmp_mode;
 643         }
 644         if (fgetxattr(fd, "user.virtfs.rdev",
 645                       &tmp_dev, sizeof(dev_t)) > 0) {
 646                 stbuf->st_rdev = tmp_dev;
 647         }
 648     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 649         errno = EOPNOTSUPP;
 650         return -1;
 651     }
 652     return err;
 653 }
 654
 655 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
 656                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 657 {
 658     char *path;
 659     int fd = -1;
 660     int err = -1;
 661     int serrno = 0;
 662     V9fsString fullname;
 663     char *buffer;
 664
 665     /*
 666      * Mark all the open to not follow symlinks
 667      */
 668     flags |= O_NOFOLLOW;
 669
 670     v9fs_string_init(&fullname);
 671     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 672     path = fullname.data;
 673
 674     /* Determine the security model */
 675     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 676         buffer = rpath(fs_ctx, path);
 677         fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
 678         if (fd == -1) {
 679             g_free(buffer);
 680             err = fd;
 681             goto out;
 682         }
 683         credp->fc_mode = credp->fc_mode|S_IFREG;
 684         /* Set cleint credentials in xattr */
 685         err = local_set_xattr(buffer, credp);
 686         if (err == -1) {
 687             serrno = errno;
 688             goto err_end;
 689         }
 690     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 691         buffer = rpath(fs_ctx, path);
 692         fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
 693         if (fd == -1) {
 694             g_free(buffer);
 695             err = fd;
 696             goto out;
 697         }
 698         credp->fc_mode = credp->fc_mode|S_IFREG;
 699         /* Set client credentials in .virtfs_metadata directory files */
 700         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 701         if (err == -1) {
 702             serrno = errno;
 703             goto err_end;
 704         }
 705     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 706                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 707         buffer = rpath(fs_ctx, path);
 708         fd = open(buffer, flags, credp->fc_mode);
 709         if (fd == -1) {
 710             g_free(buffer);
 711             err = fd;
 712             goto out;
 713         }
 714         err = local_post_create_passthrough(fs_ctx, path, credp);
 715         if (err == -1) {
 716             serrno = errno;
 717             goto err_end;
 718         }
 719     }
 720     err = fd;
 721     fs->fd = fd;
 722     goto out;
 723
 724 err_end:
 725     close(fd);
 726     remove(buffer);
 727     errno = serrno;
 728     g_free(buffer);
 729 out:
 730     v9fs_string_free(&fullname);
 731     return err;
 732 }
 733
 734
 735 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 736                          V9fsPath *dir_path, const char *name, FsCred *credp)
 737 {
 738     int err = -1;
 739     int serrno = 0;
 740     char *newpath;
 741     V9fsString fullname;
 742     char *buffer;
 743
 744     v9fs_string_init(&fullname);
 745     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 746     newpath = fullname.data;
 747
 748     /* Determine the security model */
 749     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 750         int fd;
 751         ssize_t oldpath_size, write_size;
 752         buffer = rpath(fs_ctx, newpath);
 753         fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
 754         if (fd == -1) {
 755             g_free(buffer);
 756             err = fd;
 757             goto out;
 758         }
 759         /* Write the oldpath (target) to the file. */
 760         oldpath_size = strlen(oldpath);
 761         do {
 762             write_size = write(fd, (void *)oldpath, oldpath_size);
 763         } while (write_size == -1 && errno == EINTR);
 764
 765         if (write_size != oldpath_size) {
 766             serrno = errno;
 767             close(fd);
 768             err = -1;
 769             goto err_end;
 770         }
 771         close(fd);
 772         /* Set cleint credentials in symlink's xattr */
 773         credp->fc_mode = credp->fc_mode|S_IFLNK;
 774         err = local_set_xattr(buffer, credp);
 775         if (err == -1) {
 776             serrno = errno;
 777             goto err_end;
 778         }
 779     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 780         int fd;
 781         ssize_t oldpath_size, write_size;
 782         buffer = rpath(fs_ctx, newpath);
 783         fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
 784         if (fd == -1) {
 785             g_free(buffer);
 786             err = fd;
 787             goto out;
 788         }
 789         /* Write the oldpath (target) to the file. */
 790         oldpath_size = strlen(oldpath);
 791         do {
 792             write_size = write(fd, (void *)oldpath, oldpath_size);
 793         } while (write_size == -1 && errno == EINTR);
 794
 795         if (write_size != oldpath_size) {
 796             serrno = errno;
 797             close(fd);
 798             err = -1;
 799             goto err_end;
 800         }
 801         close(fd);
 802         /* Set cleint credentials in symlink's xattr */
 803         credp->fc_mode = credp->fc_mode|S_IFLNK;
 804         err = local_set_mapped_file_attr(fs_ctx, newpath, credp);
 805         if (err == -1) {
 806             serrno = errno;
 807             goto err_end;
 808         }
 809     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 810                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 811         buffer = rpath(fs_ctx, newpath);
 812         err = symlink(oldpath, buffer);
 813         if (err) {
 814             g_free(buffer);
 815             goto out;
 816         }
 817         err = lchown(buffer, credp->fc_uid, credp->fc_gid);
 818         if (err == -1) {
 819             /*
 820              * If we fail to change ownership and if we are
 821              * using security model none. Ignore the error
 822              */
 823             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 824                 serrno = errno;
 825                 goto err_end;
 826             } else
 827                 err = 0;
 828         }
 829     }
 830     goto out;
 831
 832 err_end:
 833     remove(buffer);
 834     errno = serrno;
 835     g_free(buffer);
 836 out:
 837     v9fs_string_free(&fullname);
 838     return err;
 839 }
 840
 841 static int local_link(FsContext *ctx, V9fsPath *oldpath,
 842                       V9fsPath *dirpath, const char *name)
 843 {
 844     int ret;
 845     V9fsString newpath;
 846     char *buffer, *buffer1;
 847
 848     v9fs_string_init(&newpath);
 849     v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
 850
 851     buffer = rpath(ctx, oldpath->data);
 852     buffer1 = rpath(ctx, newpath.data);
 853     ret = link(buffer, buffer1);
 854     g_free(buffer);
 855     g_free(buffer1);
 856
 857     /* now link the virtfs_metadata files */
 858     if (!ret && (ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 859         /* Link the .virtfs_metadata files. Create the metada directory */
 860         ret = local_create_mapped_attr_dir(ctx, newpath.data);
 861         if (ret < 0) {
 862             goto err_out;
 863         }
 864         buffer = local_mapped_attr_path(ctx, oldpath->data);
 865         buffer1 = local_mapped_attr_path(ctx, newpath.data);
 866         ret = link(buffer, buffer1);
 867         g_free(buffer);
 868         g_free(buffer1);
 869         if (ret < 0 && errno != ENOENT) {
 870             goto err_out;
 871         }
 872     }
 873 err_out:
 874     v9fs_string_free(&newpath);
 875     return ret;
 876 }
 877
 878 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
 879 {
 880     char *buffer;
 881     int ret;
 882     char *path = fs_path->data;
 883
 884     buffer = rpath(ctx, path);
 885     ret = truncate(buffer, size);
 886     g_free(buffer);
 887     return ret;
 888 }
 889
 890 static int local_rename(FsContext *ctx, const char *oldpath,
 891                         const char *newpath)
 892 {
 893     int err;
 894     char *buffer, *buffer1;
 895
 896     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 897         err = local_create_mapped_attr_dir(ctx, newpath);
 898         if (err < 0) {
 899             return err;
 900         }
 901         /* rename the .virtfs_metadata files */
 902         buffer = local_mapped_attr_path(ctx, oldpath);
 903         buffer1 = local_mapped_attr_path(ctx, newpath);
 904         err = rename(buffer, buffer1);
 905         g_free(buffer);
 906         g_free(buffer1);
 907         if (err < 0 && errno != ENOENT) {
 908             return err;
 909         }
 910     }
 911
 912     buffer = rpath(ctx, oldpath);
 913     buffer1 = rpath(ctx, newpath);
 914     err = rename(buffer, buffer1);
 915     g_free(buffer);
 916     g_free(buffer1);
 917     return err;
 918 }
 919
 920 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 921 {
 922     char *buffer;
 923     int ret = -1;
 924     char *path = fs_path->data;
 925
 926     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
 927         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 928         (fs_ctx->export_flags & V9FS_SM_NONE)) {
 929         buffer = rpath(fs_ctx, path);
 930         ret = lchown(buffer, credp->fc_uid, credp->fc_gid);
 931         g_free(buffer);
 932     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 933         buffer = rpath(fs_ctx, path);
 934         ret = local_set_xattr(buffer, credp);
 935         g_free(buffer);
 936     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 937         return local_set_mapped_file_attr(fs_ctx, path, credp);
 938     }
 939     return ret;
 940 }
 941
 942 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
 943                            const struct timespec *buf)
 944 {
 945     char *buffer;
 946     int ret;
 947     char *path = fs_path->data;
 948
 949     buffer = rpath(s, path);
 950     ret = qemu_utimens(buffer, buf);
 951     g_free(buffer);
 952     return ret;
 953 }
 954
 955 static int local_remove(FsContext *ctx, const char *path)
 956 {
 957     int err;
 958     struct stat stbuf;
 959     char *buffer;
 960
 961     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 962         buffer = rpath(ctx, path);
 963         err =  lstat(buffer, &stbuf);
 964         g_free(buffer);
 965         if (err) {
 966             goto err_out;
 967         }
 968         /*
 969          * If directory remove .virtfs_metadata contained in the
 970          * directory
 971          */
 972         if (S_ISDIR(stbuf.st_mode)) {
 973             buffer = g_strdup_printf("%s/%s/%s", ctx->fs_root,
 974                                      path, VIRTFS_META_DIR);
 975             err = remove(buffer);
 976             g_free(buffer);
 977             if (err < 0 && errno != ENOENT) {
 978                 /*
 979                  * We didn't had the .virtfs_metadata file. May be file created
 980                  * in non-mapped mode ?. Ignore ENOENT.
 981                  */
 982                 goto err_out;
 983             }
 984         }
 985         /*
 986          * Now remove the name from parent directory
 987          * .virtfs_metadata directory
 988          */
 989         buffer = local_mapped_attr_path(ctx, path);
 990         err = remove(buffer);
 991         g_free(buffer);
 992         if (err < 0 && errno != ENOENT) {
 993             /*
 994              * We didn't had the .virtfs_metadata file. May be file created
 995              * in non-mapped mode ?. Ignore ENOENT.
 996              */
 997             goto err_out;
 998         }
 999     }
1000
1001     buffer = rpath(ctx, path);
1002     err = remove(buffer);
1003     g_free(buffer);
1004 err_out:
1005     return err;
1006 }
1007
1008 static int local_fsync(FsContext *ctx, int fid_type,
1009                        V9fsFidOpenState *fs, int datasync)
1010 {
1011     int fd;
1012
1013     if (fid_type == P9_FID_DIR) {
1014         fd = dirfd(fs->dir);
1015     } else {
1016         fd = fs->fd;
1017     }
1018
1019     if (datasync) {
1020         return qemu_fdatasync(fd);
1021     } else {
1022         return fsync(fd);
1023     }
1024 }
1025
1026 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
1027 {
1028     char *buffer;
1029     int ret;
1030     char *path = fs_path->data;
1031
1032     buffer = rpath(s, path);
1033     ret = statfs(buffer, stbuf);
1034     g_free(buffer);
1035     return ret;
1036 }
1037
1038 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
1039                                const char *name, void *value, size_t size)
1040 {
1041     char *path = fs_path->data;
1042
1043     return v9fs_get_xattr(ctx, path, name, value, size);
1044 }
1045
1046 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
1047                                 void *value, size_t size)
1048 {
1049     char *path = fs_path->data;
1050
1051     return v9fs_list_xattr(ctx, path, value, size);
1052 }
1053
1054 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
1055                            void *value, size_t size, int flags)
1056 {
1057     char *path = fs_path->data;
1058
1059     return v9fs_set_xattr(ctx, path, name, value, size, flags);
1060 }
1061
1062 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
1063                               const char *name)
1064 {
1065     char *path = fs_path->data;
1066
1067     return v9fs_remove_xattr(ctx, path, name);
1068 }
1069
1070 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
1071                               const char *name, V9fsPath *target)
1072 {
1073     if (dir_path) {
1074         v9fs_string_sprintf((V9fsString *)target, "%s/%s",
1075                             dir_path->data, name);
1076     } else {
1077         v9fs_string_sprintf((V9fsString *)target, "%s", name);
1078     }
1079     /* Bump the size for including terminating NULL */
1080     target->size++;
1081     return 0;
1082 }
1083
1084 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
1085                           const char *old_name, V9fsPath *newdir,
1086                           const char *new_name)
1087 {
1088     int ret;
1089     V9fsString old_full_name, new_full_name;
1090
1091     v9fs_string_init(&old_full_name);
1092     v9fs_string_init(&new_full_name);
1093
1094     v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
1095     v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
1096
1097     ret = local_rename(ctx, old_full_name.data, new_full_name.data);
1098     v9fs_string_free(&old_full_name);
1099     v9fs_string_free(&new_full_name);
1100     return ret;
1101 }
1102
1103 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
1104                           const char *name, int flags)
1105 {
1106     int ret;
1107     V9fsString fullname;
1108     char *buffer;
1109
1110     v9fs_string_init(&fullname);
1111
1112     v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
1113     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1114         if (flags == AT_REMOVEDIR) {
1115             /*
1116              * If directory remove .virtfs_metadata contained in the
1117              * directory
1118              */
1119             buffer = g_strdup_printf("%s/%s/%s", ctx->fs_root,
1120                                      fullname.data, VIRTFS_META_DIR);
1121             ret = remove(buffer);
1122             g_free(buffer);
1123             if (ret < 0 && errno != ENOENT) {
1124                 /*
1125                  * We didn't had the .virtfs_metadata file. May be file created
1126                  * in non-mapped mode ?. Ignore ENOENT.
1127                  */
1128                 goto err_out;
1129             }
1130         }
1131         /*
1132          * Now remove the name from parent directory
1133          * .virtfs_metadata directory.
1134          */
1135         buffer = local_mapped_attr_path(ctx, fullname.data);
1136         ret = remove(buffer);
1137         g_free(buffer);
1138         if (ret < 0 && errno != ENOENT) {
1139             /*
1140              * We didn't had the .virtfs_metadata file. May be file created
1141              * in non-mapped mode ?. Ignore ENOENT.
1142              */
1143             goto err_out;
1144         }
1145     }
1146     /* Remove the name finally */
1147     buffer = rpath(ctx, fullname.data);
1148     ret = remove(buffer);
1149     g_free(buffer);
1150
1151 err_out:
1152     v9fs_string_free(&fullname);
1153     return ret;
1154 }
1155
1156 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1157                                 mode_t st_mode, uint64_t *st_gen)
1158 {
1159 #ifdef FS_IOC_GETVERSION
1160     int err;
1161     V9fsFidOpenState fid_open;
1162
1163     /*
1164      * Do not try to open special files like device nodes, fifos etc
1165      * We can get fd for regular files and directories only
1166      */
1167     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1168         errno = ENOTTY;
1169         return -1;
1170     }
1171     err = local_open(ctx, path, O_RDONLY, &fid_open);
1172     if (err < 0) {
1173         return err;
1174     }
1175     err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1176     local_close(ctx, &fid_open);
1177     return err;
1178 #else
1179     errno = ENOTTY;
1180     return -1;
1181 #endif
1182 }
1183
1184 static int local_init(FsContext *ctx)
1185 {
1186     int err = 0;
1187     struct statfs stbuf;
1188
1189     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1190         ctx->xops = passthrough_xattr_ops;
1191     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1192         ctx->xops = mapped_xattr_ops;
1193     } else if (ctx->export_flags & V9FS_SM_NONE) {
1194         ctx->xops = none_xattr_ops;
1195     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1196         /*
1197          * xattr operation for mapped-file and passthrough
1198          * remain same.
1199          */
1200         ctx->xops = passthrough_xattr_ops;
1201     }
1202     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1203 #ifdef FS_IOC_GETVERSION
1204     /*
1205      * use ioc_getversion only if the iocl is definied
1206      */
1207     err = statfs(ctx->fs_root, &stbuf);
1208     if (!err) {
1209         switch (stbuf.f_type) {
1210         case EXT2_SUPER_MAGIC:
1211         case BTRFS_SUPER_MAGIC:
1212         case REISERFS_SUPER_MAGIC:
1213         case XFS_SUPER_MAGIC:
1214             ctx->exops.get_st_gen = local_ioc_getversion;
1215             break;
1216         }
1217     }
1218 #endif
1219     return err;
1220 }
1221
1222 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
1223 {
1224     const char *sec_model = qemu_opt_get(opts, "security_model");
1225     const char *path = qemu_opt_get(opts, "path");
1226
1227     if (!sec_model) {
1228         fprintf(stderr, "security model not specified, "
1229                 "local fs needs security model\nvalid options are:"
1230                 "\tsecurity_model=[passthrough|mapped|none]\n");
1231         return -1;
1232     }
1233
1234     if (!strcmp(sec_model, "passthrough")) {
1235         fse->export_flags |= V9FS_SM_PASSTHROUGH;
1236     } else if (!strcmp(sec_model, "mapped") ||
1237                !strcmp(sec_model, "mapped-xattr")) {
1238         fse->export_flags |= V9FS_SM_MAPPED;
1239     } else if (!strcmp(sec_model, "none")) {
1240         fse->export_flags |= V9FS_SM_NONE;
1241     } else if (!strcmp(sec_model, "mapped-file")) {
1242         fse->export_flags |= V9FS_SM_MAPPED_FILE;
1243     } else {
1244         fprintf(stderr, "Invalid security model %s specified, valid options are"
1245                 "\n\t [passthrough|mapped-xattr|mapped-file|none]\n",
1246                 sec_model);
1247         return -1;
1248     }
1249
1250     if (!path) {
1251         fprintf(stderr, "fsdev: No path specified.\n");
1252         return -1;
1253     }
1254     fse->path = g_strdup(path);
1255
1256     return 0;
1257 }
1258
1259 FileOperations local_ops = {
1260     .parse_opts = local_parse_opts,
1261     .init  = local_init,
1262     .lstat = local_lstat,
1263     .readlink = local_readlink,
1264     .close = local_close,
1265     .closedir = local_closedir,
1266     .open = local_open,
1267     .opendir = local_opendir,
1268     .rewinddir = local_rewinddir,
1269     .telldir = local_telldir,
1270     .readdir_r = local_readdir_r,
1271     .seekdir = local_seekdir,
1272     .preadv = local_preadv,
1273     .pwritev = local_pwritev,
1274     .chmod = local_chmod,
1275     .mknod = local_mknod,
1276     .mkdir = local_mkdir,
1277     .fstat = local_fstat,
1278     .open2 = local_open2,
1279     .symlink = local_symlink,
1280     .link = local_link,
1281     .truncate = local_truncate,
1282     .rename = local_rename,
1283     .chown = local_chown,
1284     .utimensat = local_utimensat,
1285     .remove = local_remove,
1286     .fsync = local_fsync,
1287     .statfs = local_statfs,
1288     .lgetxattr = local_lgetxattr,
1289     .llistxattr = local_llistxattr,
1290     .lsetxattr = local_lsetxattr,
1291     .lremovexattr = local_lremovexattr,
1292     .name_to_path = local_name_to_path,
1293     .renameat  = local_renameat,
1294     .unlinkat = local_unlinkat,
1295 };