hw/9pfs/9p-local.c

   1 /*
   2  * 9p Posix callback
   3  *
   4  * Copyright IBM, Corp. 2010
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include "9p.h"
  16 #include "9p-local.h"
  17 #include "9p-xattr.h"
  18 #include "9p-util.h"
  19 #include "fsdev/qemu-fsdev.h"   /* local_ops */
  20 #include <arpa/inet.h>
  21 #include <pwd.h>
  22 #include <grp.h>
  23 #include <sys/socket.h>
  24 #include <sys/un.h>
  25 #include "qemu/xattr.h"
  26 #include "qemu/cutils.h"
  27 #include "qemu/error-report.h"
  28 #include <libgen.h>
  29 #include <linux/fs.h>
  30 #ifdef CONFIG_LINUX_MAGIC_H
  31 #include <linux/magic.h>
  32 #endif
  33 #include <sys/ioctl.h>
  34
  35 #ifndef XFS_SUPER_MAGIC
  36 #define XFS_SUPER_MAGIC  0x58465342
  37 #endif
  38 #ifndef EXT2_SUPER_MAGIC
  39 #define EXT2_SUPER_MAGIC 0xEF53
  40 #endif
  41 #ifndef REISERFS_SUPER_MAGIC
  42 #define REISERFS_SUPER_MAGIC 0x52654973
  43 #endif
  44 #ifndef BTRFS_SUPER_MAGIC
  45 #define BTRFS_SUPER_MAGIC 0x9123683E
  46 #endif
  47
  48 typedef struct {
  49     int mountfd;
  50 } LocalData;
  51
  52 int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
  53                         mode_t mode)
  54 {
  55     LocalData *data = fs_ctx->private;
  56
  57     /* All paths are relative to the path data->mountfd points to */
  58     while (*path == '/') {
  59         path++;
  60     }
  61
  62     return relative_openat_nofollow(data->mountfd, path, flags, mode);
  63 }
  64
  65 int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
  66 {
  67     return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0);
  68 }
  69
  70 #define VIRTFS_META_DIR ".virtfs_metadata"
  71
  72 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
  73 {
  74     int dirlen;
  75     const char *name = strrchr(path, '/');
  76     if (name) {
  77         dirlen = name - path;
  78         ++name;
  79     } else {
  80         name = path;
  81         dirlen = 0;
  82     }
  83     return g_strdup_printf("%s/%.*s/%s/%s", ctx->fs_root,
  84                            dirlen, path, VIRTFS_META_DIR, name);
  85 }
  86
  87 static FILE *local_fopen(const char *path, const char *mode)
  88 {
  89     int fd, o_mode = 0;
  90     FILE *fp;
  91     int flags = O_NOFOLLOW;
  92     /*
  93      * only supports two modes
  94      */
  95     if (mode[0] == 'r') {
  96         flags |= O_RDONLY;
  97     } else if (mode[0] == 'w') {
  98         flags |= O_WRONLY | O_TRUNC | O_CREAT;
  99         o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
 100     } else {
 101         return NULL;
 102     }
 103     fd = open(path, flags, o_mode);
 104     if (fd == -1) {
 105         return NULL;
 106     }
 107     fp = fdopen(fd, mode);
 108     if (!fp) {
 109         close(fd);
 110     }
 111     return fp;
 112 }
 113
 114 #define ATTR_MAX 100
 115 static void local_mapped_file_attr(FsContext *ctx, const char *path,
 116                                    struct stat *stbuf)
 117 {
 118     FILE *fp;
 119     char buf[ATTR_MAX];
 120     char *attr_path;
 121
 122     attr_path = local_mapped_attr_path(ctx, path);
 123     fp = local_fopen(attr_path, "r");
 124     g_free(attr_path);
 125     if (!fp) {
 126         return;
 127     }
 128     memset(buf, 0, ATTR_MAX);
 129     while (fgets(buf, ATTR_MAX, fp)) {
 130         if (!strncmp(buf, "virtfs.uid", 10)) {
 131             stbuf->st_uid = atoi(buf+11);
 132         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 133             stbuf->st_gid = atoi(buf+11);
 134         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 135             stbuf->st_mode = atoi(buf+12);
 136         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 137             stbuf->st_rdev = atoi(buf+12);
 138         }
 139         memset(buf, 0, ATTR_MAX);
 140     }
 141     fclose(fp);
 142 }
 143
 144 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
 145 {
 146     int err;
 147     char *buffer;
 148     char *path = fs_path->data;
 149
 150     buffer = rpath(fs_ctx, path);
 151     err =  lstat(buffer, stbuf);
 152     if (err) {
 153         goto err_out;
 154     }
 155     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 156         /* Actual credentials are part of extended attrs */
 157         uid_t tmp_uid;
 158         gid_t tmp_gid;
 159         mode_t tmp_mode;
 160         dev_t tmp_dev;
 161         if (getxattr(buffer, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
 162             stbuf->st_uid = le32_to_cpu(tmp_uid);
 163         }
 164         if (getxattr(buffer, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
 165             stbuf->st_gid = le32_to_cpu(tmp_gid);
 166         }
 167         if (getxattr(buffer, "user.virtfs.mode",
 168                     &tmp_mode, sizeof(mode_t)) > 0) {
 169             stbuf->st_mode = le32_to_cpu(tmp_mode);
 170         }
 171         if (getxattr(buffer, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
 172             stbuf->st_rdev = le64_to_cpu(tmp_dev);
 173         }
 174     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 175         local_mapped_file_attr(fs_ctx, path, stbuf);
 176     }
 177
 178 err_out:
 179     g_free(buffer);
 180     return err;
 181 }
 182
 183 static int local_create_mapped_attr_dir(FsContext *ctx, const char *path)
 184 {
 185     int err;
 186     char *attr_dir;
 187     char *tmp_path = g_strdup(path);
 188
 189     attr_dir = g_strdup_printf("%s/%s/%s",
 190              ctx->fs_root, dirname(tmp_path), VIRTFS_META_DIR);
 191
 192     err = mkdir(attr_dir, 0700);
 193     if (err < 0 && errno == EEXIST) {
 194         err = 0;
 195     }
 196     g_free(attr_dir);
 197     g_free(tmp_path);
 198     return err;
 199 }
 200
 201 static int local_set_mapped_file_attr(FsContext *ctx,
 202                                       const char *path, FsCred *credp)
 203 {
 204     FILE *fp;
 205     int ret = 0;
 206     char buf[ATTR_MAX];
 207     char *attr_path;
 208     int uid = -1, gid = -1, mode = -1, rdev = -1;
 209
 210     attr_path = local_mapped_attr_path(ctx, path);
 211     fp = local_fopen(attr_path, "r");
 212     if (!fp) {
 213         goto create_map_file;
 214     }
 215     memset(buf, 0, ATTR_MAX);
 216     while (fgets(buf, ATTR_MAX, fp)) {
 217         if (!strncmp(buf, "virtfs.uid", 10)) {
 218             uid = atoi(buf+11);
 219         } else if (!strncmp(buf, "virtfs.gid", 10)) {
 220             gid = atoi(buf+11);
 221         } else if (!strncmp(buf, "virtfs.mode", 11)) {
 222             mode = atoi(buf+12);
 223         } else if (!strncmp(buf, "virtfs.rdev", 11)) {
 224             rdev = atoi(buf+12);
 225         }
 226         memset(buf, 0, ATTR_MAX);
 227     }
 228     fclose(fp);
 229     goto update_map_file;
 230
 231 create_map_file:
 232     ret = local_create_mapped_attr_dir(ctx, path);
 233     if (ret < 0) {
 234         goto err_out;
 235     }
 236
 237 update_map_file:
 238     fp = local_fopen(attr_path, "w");
 239     if (!fp) {
 240         ret = -1;
 241         goto err_out;
 242     }
 243
 244     if (credp->fc_uid != -1) {
 245         uid = credp->fc_uid;
 246     }
 247     if (credp->fc_gid != -1) {
 248         gid = credp->fc_gid;
 249     }
 250     if (credp->fc_mode != -1) {
 251         mode = credp->fc_mode;
 252     }
 253     if (credp->fc_rdev != -1) {
 254         rdev = credp->fc_rdev;
 255     }
 256
 257
 258     if (uid != -1) {
 259         fprintf(fp, "virtfs.uid=%d\n", uid);
 260     }
 261     if (gid != -1) {
 262         fprintf(fp, "virtfs.gid=%d\n", gid);
 263     }
 264     if (mode != -1) {
 265         fprintf(fp, "virtfs.mode=%d\n", mode);
 266     }
 267     if (rdev != -1) {
 268         fprintf(fp, "virtfs.rdev=%d\n", rdev);
 269     }
 270     fclose(fp);
 271
 272 err_out:
 273     g_free(attr_path);
 274     return ret;
 275 }
 276
 277 static int local_set_xattr(const char *path, FsCred *credp)
 278 {
 279     int err;
 280
 281     if (credp->fc_uid != -1) {
 282         uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
 283         err = setxattr(path, "user.virtfs.uid", &tmp_uid, sizeof(uid_t), 0);
 284         if (err) {
 285             return err;
 286         }
 287     }
 288     if (credp->fc_gid != -1) {
 289         uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
 290         err = setxattr(path, "user.virtfs.gid", &tmp_gid, sizeof(gid_t), 0);
 291         if (err) {
 292             return err;
 293         }
 294     }
 295     if (credp->fc_mode != -1) {
 296         uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
 297         err = setxattr(path, "user.virtfs.mode", &tmp_mode, sizeof(mode_t), 0);
 298         if (err) {
 299             return err;
 300         }
 301     }
 302     if (credp->fc_rdev != -1) {
 303         uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
 304         err = setxattr(path, "user.virtfs.rdev", &tmp_rdev, sizeof(dev_t), 0);
 305         if (err) {
 306             return err;
 307         }
 308     }
 309     return 0;
 310 }
 311
 312 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
 313                                          FsCred *credp)
 314 {
 315     char *buffer;
 316
 317     buffer = rpath(fs_ctx, path);
 318     if (lchown(buffer, credp->fc_uid, credp->fc_gid) < 0) {
 319         /*
 320          * If we fail to change ownership and if we are
 321          * using security model none. Ignore the error
 322          */
 323         if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 324             goto err;
 325         }
 326     }
 327
 328     if (chmod(buffer, credp->fc_mode & 07777) < 0) {
 329         goto err;
 330     }
 331
 332     g_free(buffer);
 333     return 0;
 334 err:
 335     g_free(buffer);
 336     return -1;
 337 }
 338
 339 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
 340                               char *buf, size_t bufsz)
 341 {
 342     ssize_t tsize = -1;
 343     char *buffer;
 344     char *path = fs_path->data;
 345
 346     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
 347         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 348         int fd;
 349         buffer = rpath(fs_ctx, path);
 350         fd = open(buffer, O_RDONLY | O_NOFOLLOW);
 351         g_free(buffer);
 352         if (fd == -1) {
 353             return -1;
 354         }
 355         do {
 356             tsize = read(fd, (void *)buf, bufsz);
 357         } while (tsize == -1 && errno == EINTR);
 358         close(fd);
 359     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 360                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 361         buffer = rpath(fs_ctx, path);
 362         tsize = readlink(buffer, buf, bufsz);
 363         g_free(buffer);
 364     }
 365     return tsize;
 366 }
 367
 368 static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
 369 {
 370     return close(fs->fd);
 371 }
 372
 373 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 374 {
 375     return closedir(fs->dir.stream);
 376 }
 377
 378 static int local_open(FsContext *ctx, V9fsPath *fs_path,
 379                       int flags, V9fsFidOpenState *fs)
 380 {
 381     int fd;
 382
 383     fd = local_open_nofollow(ctx, fs_path->data, flags, 0);
 384     if (fd == -1) {
 385         return -1;
 386     }
 387     fs->fd = fd;
 388     return fs->fd;
 389 }
 390
 391 static int local_opendir(FsContext *ctx,
 392                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 393 {
 394     int dirfd;
 395     DIR *stream;
 396
 397     dirfd = local_opendir_nofollow(ctx, fs_path->data);
 398     if (dirfd == -1) {
 399         return -1;
 400     }
 401
 402     stream = fdopendir(dirfd);
 403     if (!stream) {
 404         return -1;
 405     }
 406     fs->dir.stream = stream;
 407     return 0;
 408 }
 409
 410 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 411 {
 412     rewinddir(fs->dir.stream);
 413 }
 414
 415 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 416 {
 417     return telldir(fs->dir.stream);
 418 }
 419
 420 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs)
 421 {
 422     struct dirent *entry;
 423
 424 again:
 425     entry = readdir(fs->dir.stream);
 426     if (!entry) {
 427         return NULL;
 428     }
 429
 430     if (ctx->export_flags & V9FS_SM_MAPPED) {
 431         entry->d_type = DT_UNKNOWN;
 432     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 433         if (!strcmp(entry->d_name, VIRTFS_META_DIR)) {
 434             /* skp the meta data directory */
 435             goto again;
 436         }
 437         entry->d_type = DT_UNKNOWN;
 438     }
 439
 440     return entry;
 441 }
 442
 443 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 444 {
 445     seekdir(fs->dir.stream, off);
 446 }
 447
 448 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
 449                             const struct iovec *iov,
 450                             int iovcnt, off_t offset)
 451 {
 452 #ifdef CONFIG_PREADV
 453     return preadv(fs->fd, iov, iovcnt, offset);
 454 #else
 455     int err = lseek(fs->fd, offset, SEEK_SET);
 456     if (err == -1) {
 457         return err;
 458     } else {
 459         return readv(fs->fd, iov, iovcnt);
 460     }
 461 #endif
 462 }
 463
 464 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 465                              const struct iovec *iov,
 466                              int iovcnt, off_t offset)
 467 {
 468     ssize_t ret;
 469 #ifdef CONFIG_PREADV
 470     ret = pwritev(fs->fd, iov, iovcnt, offset);
 471 #else
 472     int err = lseek(fs->fd, offset, SEEK_SET);
 473     if (err == -1) {
 474         return err;
 475     } else {
 476         ret = writev(fs->fd, iov, iovcnt);
 477     }
 478 #endif
 479 #ifdef CONFIG_SYNC_FILE_RANGE
 480     if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
 481         /*
 482          * Initiate a writeback. This is not a data integrity sync.
 483          * We want to ensure that we don't leave dirty pages in the cache
 484          * after write when writeout=immediate is sepcified.
 485          */
 486         sync_file_range(fs->fd, offset, ret,
 487                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
 488     }
 489 #endif
 490     return ret;
 491 }
 492
 493 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 494 {
 495     char *buffer;
 496     int ret = -1;
 497     char *path = fs_path->data;
 498
 499     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 500         buffer = rpath(fs_ctx, path);
 501         ret = local_set_xattr(buffer, credp);
 502         g_free(buffer);
 503     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 504         return local_set_mapped_file_attr(fs_ctx, path, credp);
 505     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 506                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 507         buffer = rpath(fs_ctx, path);
 508         ret = chmod(buffer, credp->fc_mode);
 509         g_free(buffer);
 510     }
 511     return ret;
 512 }
 513
 514 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
 515                        const char *name, FsCred *credp)
 516 {
 517     char *path;
 518     int err = -1;
 519     int serrno = 0;
 520     V9fsString fullname;
 521     char *buffer = NULL;
 522
 523     v9fs_string_init(&fullname);
 524     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 525     path = fullname.data;
 526
 527     /* Determine the security model */
 528     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 529         buffer = rpath(fs_ctx, path);
 530         err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
 531         if (err == -1) {
 532             goto out;
 533         }
 534         err = local_set_xattr(buffer, credp);
 535         if (err == -1) {
 536             serrno = errno;
 537             goto err_end;
 538         }
 539     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 540
 541         buffer = rpath(fs_ctx, path);
 542         err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
 543         if (err == -1) {
 544             goto out;
 545         }
 546         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 547         if (err == -1) {
 548             serrno = errno;
 549             goto err_end;
 550         }
 551     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 552                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 553         buffer = rpath(fs_ctx, path);
 554         err = mknod(buffer, credp->fc_mode, credp->fc_rdev);
 555         if (err == -1) {
 556             goto out;
 557         }
 558         err = local_post_create_passthrough(fs_ctx, path, credp);
 559         if (err == -1) {
 560             serrno = errno;
 561             goto err_end;
 562         }
 563     }
 564     goto out;
 565
 566 err_end:
 567     remove(buffer);
 568     errno = serrno;
 569 out:
 570     g_free(buffer);
 571     v9fs_string_free(&fullname);
 572     return err;
 573 }
 574
 575 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
 576                        const char *name, FsCred *credp)
 577 {
 578     char *path;
 579     int err = -1;
 580     int serrno = 0;
 581     V9fsString fullname;
 582     char *buffer = NULL;
 583
 584     v9fs_string_init(&fullname);
 585     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 586     path = fullname.data;
 587
 588     /* Determine the security model */
 589     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 590         buffer = rpath(fs_ctx, path);
 591         err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
 592         if (err == -1) {
 593             goto out;
 594         }
 595         credp->fc_mode = credp->fc_mode|S_IFDIR;
 596         err = local_set_xattr(buffer, credp);
 597         if (err == -1) {
 598             serrno = errno;
 599             goto err_end;
 600         }
 601     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 602         buffer = rpath(fs_ctx, path);
 603         err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
 604         if (err == -1) {
 605             goto out;
 606         }
 607         credp->fc_mode = credp->fc_mode|S_IFDIR;
 608         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 609         if (err == -1) {
 610             serrno = errno;
 611             goto err_end;
 612         }
 613     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 614                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 615         buffer = rpath(fs_ctx, path);
 616         err = mkdir(buffer, credp->fc_mode);
 617         if (err == -1) {
 618             goto out;
 619         }
 620         err = local_post_create_passthrough(fs_ctx, path, credp);
 621         if (err == -1) {
 622             serrno = errno;
 623             goto err_end;
 624         }
 625     }
 626     goto out;
 627
 628 err_end:
 629     remove(buffer);
 630     errno = serrno;
 631 out:
 632     g_free(buffer);
 633     v9fs_string_free(&fullname);
 634     return err;
 635 }
 636
 637 static int local_fstat(FsContext *fs_ctx, int fid_type,
 638                        V9fsFidOpenState *fs, struct stat *stbuf)
 639 {
 640     int err, fd;
 641
 642     if (fid_type == P9_FID_DIR) {
 643         fd = dirfd(fs->dir.stream);
 644     } else {
 645         fd = fs->fd;
 646     }
 647
 648     err = fstat(fd, stbuf);
 649     if (err) {
 650         return err;
 651     }
 652     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 653         /* Actual credentials are part of extended attrs */
 654         uid_t tmp_uid;
 655         gid_t tmp_gid;
 656         mode_t tmp_mode;
 657         dev_t tmp_dev;
 658
 659         if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
 660             stbuf->st_uid = le32_to_cpu(tmp_uid);
 661         }
 662         if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
 663             stbuf->st_gid = le32_to_cpu(tmp_gid);
 664         }
 665         if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
 666             stbuf->st_mode = le32_to_cpu(tmp_mode);
 667         }
 668         if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
 669             stbuf->st_rdev = le64_to_cpu(tmp_dev);
 670         }
 671     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 672         errno = EOPNOTSUPP;
 673         return -1;
 674     }
 675     return err;
 676 }
 677
 678 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
 679                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 680 {
 681     char *path;
 682     int fd = -1;
 683     int err = -1;
 684     int serrno = 0;
 685     V9fsString fullname;
 686     char *buffer = NULL;
 687
 688     /*
 689      * Mark all the open to not follow symlinks
 690      */
 691     flags |= O_NOFOLLOW;
 692
 693     v9fs_string_init(&fullname);
 694     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 695     path = fullname.data;
 696
 697     /* Determine the security model */
 698     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 699         buffer = rpath(fs_ctx, path);
 700         fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
 701         if (fd == -1) {
 702             err = fd;
 703             goto out;
 704         }
 705         credp->fc_mode = credp->fc_mode|S_IFREG;
 706         /* Set cleint credentials in xattr */
 707         err = local_set_xattr(buffer, credp);
 708         if (err == -1) {
 709             serrno = errno;
 710             goto err_end;
 711         }
 712     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 713         buffer = rpath(fs_ctx, path);
 714         fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
 715         if (fd == -1) {
 716             err = fd;
 717             goto out;
 718         }
 719         credp->fc_mode = credp->fc_mode|S_IFREG;
 720         /* Set client credentials in .virtfs_metadata directory files */
 721         err = local_set_mapped_file_attr(fs_ctx, path, credp);
 722         if (err == -1) {
 723             serrno = errno;
 724             goto err_end;
 725         }
 726     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 727                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 728         buffer = rpath(fs_ctx, path);
 729         fd = open(buffer, flags, credp->fc_mode);
 730         if (fd == -1) {
 731             err = fd;
 732             goto out;
 733         }
 734         err = local_post_create_passthrough(fs_ctx, path, credp);
 735         if (err == -1) {
 736             serrno = errno;
 737             goto err_end;
 738         }
 739     }
 740     err = fd;
 741     fs->fd = fd;
 742     goto out;
 743
 744 err_end:
 745     close(fd);
 746     remove(buffer);
 747     errno = serrno;
 748 out:
 749     g_free(buffer);
 750     v9fs_string_free(&fullname);
 751     return err;
 752 }
 753
 754
 755 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 756                          V9fsPath *dir_path, const char *name, FsCred *credp)
 757 {
 758     int err = -1;
 759     int serrno = 0;
 760     char *newpath;
 761     V9fsString fullname;
 762     char *buffer = NULL;
 763
 764     v9fs_string_init(&fullname);
 765     v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
 766     newpath = fullname.data;
 767
 768     /* Determine the security model */
 769     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 770         int fd;
 771         ssize_t oldpath_size, write_size;
 772         buffer = rpath(fs_ctx, newpath);
 773         fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
 774         if (fd == -1) {
 775             err = fd;
 776             goto out;
 777         }
 778         /* Write the oldpath (target) to the file. */
 779         oldpath_size = strlen(oldpath);
 780         do {
 781             write_size = write(fd, (void *)oldpath, oldpath_size);
 782         } while (write_size == -1 && errno == EINTR);
 783
 784         if (write_size != oldpath_size) {
 785             serrno = errno;
 786             close(fd);
 787             err = -1;
 788             goto err_end;
 789         }
 790         close(fd);
 791         /* Set cleint credentials in symlink's xattr */
 792         credp->fc_mode = credp->fc_mode|S_IFLNK;
 793         err = local_set_xattr(buffer, credp);
 794         if (err == -1) {
 795             serrno = errno;
 796             goto err_end;
 797         }
 798     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 799         int fd;
 800         ssize_t oldpath_size, write_size;
 801         buffer = rpath(fs_ctx, newpath);
 802         fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
 803         if (fd == -1) {
 804             err = fd;
 805             goto out;
 806         }
 807         /* Write the oldpath (target) to the file. */
 808         oldpath_size = strlen(oldpath);
 809         do {
 810             write_size = write(fd, (void *)oldpath, oldpath_size);
 811         } while (write_size == -1 && errno == EINTR);
 812
 813         if (write_size != oldpath_size) {
 814             serrno = errno;
 815             close(fd);
 816             err = -1;
 817             goto err_end;
 818         }
 819         close(fd);
 820         /* Set cleint credentials in symlink's xattr */
 821         credp->fc_mode = credp->fc_mode|S_IFLNK;
 822         err = local_set_mapped_file_attr(fs_ctx, newpath, credp);
 823         if (err == -1) {
 824             serrno = errno;
 825             goto err_end;
 826         }
 827     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 828                (fs_ctx->export_flags & V9FS_SM_NONE)) {
 829         buffer = rpath(fs_ctx, newpath);
 830         err = symlink(oldpath, buffer);
 831         if (err) {
 832             goto out;
 833         }
 834         err = lchown(buffer, credp->fc_uid, credp->fc_gid);
 835         if (err == -1) {
 836             /*
 837              * If we fail to change ownership and if we are
 838              * using security model none. Ignore the error
 839              */
 840             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
 841                 serrno = errno;
 842                 goto err_end;
 843             } else
 844                 err = 0;
 845         }
 846     }
 847     goto out;
 848
 849 err_end:
 850     remove(buffer);
 851     errno = serrno;
 852 out:
 853     g_free(buffer);
 854     v9fs_string_free(&fullname);
 855     return err;
 856 }
 857
 858 static int local_link(FsContext *ctx, V9fsPath *oldpath,
 859                       V9fsPath *dirpath, const char *name)
 860 {
 861     int ret;
 862     V9fsString newpath;
 863     char *buffer, *buffer1;
 864
 865     v9fs_string_init(&newpath);
 866     v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
 867
 868     buffer = rpath(ctx, oldpath->data);
 869     buffer1 = rpath(ctx, newpath.data);
 870     ret = link(buffer, buffer1);
 871     g_free(buffer);
 872     g_free(buffer1);
 873
 874     /* now link the virtfs_metadata files */
 875     if (!ret && (ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
 876         /* Link the .virtfs_metadata files. Create the metada directory */
 877         ret = local_create_mapped_attr_dir(ctx, newpath.data);
 878         if (ret < 0) {
 879             goto err_out;
 880         }
 881         buffer = local_mapped_attr_path(ctx, oldpath->data);
 882         buffer1 = local_mapped_attr_path(ctx, newpath.data);
 883         ret = link(buffer, buffer1);
 884         g_free(buffer);
 885         g_free(buffer1);
 886         if (ret < 0 && errno != ENOENT) {
 887             goto err_out;
 888         }
 889     }
 890 err_out:
 891     v9fs_string_free(&newpath);
 892     return ret;
 893 }
 894
 895 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
 896 {
 897     char *buffer;
 898     int ret;
 899     char *path = fs_path->data;
 900
 901     buffer = rpath(ctx, path);
 902     ret = truncate(buffer, size);
 903     g_free(buffer);
 904     return ret;
 905 }
 906
 907 static int local_rename(FsContext *ctx, const char *oldpath,
 908                         const char *newpath)
 909 {
 910     int err;
 911     char *buffer, *buffer1;
 912
 913     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 914         err = local_create_mapped_attr_dir(ctx, newpath);
 915         if (err < 0) {
 916             return err;
 917         }
 918         /* rename the .virtfs_metadata files */
 919         buffer = local_mapped_attr_path(ctx, oldpath);
 920         buffer1 = local_mapped_attr_path(ctx, newpath);
 921         err = rename(buffer, buffer1);
 922         g_free(buffer);
 923         g_free(buffer1);
 924         if (err < 0 && errno != ENOENT) {
 925             return err;
 926         }
 927     }
 928
 929     buffer = rpath(ctx, oldpath);
 930     buffer1 = rpath(ctx, newpath);
 931     err = rename(buffer, buffer1);
 932     g_free(buffer);
 933     g_free(buffer1);
 934     return err;
 935 }
 936
 937 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 938 {
 939     char *buffer;
 940     int ret = -1;
 941     char *path = fs_path->data;
 942
 943     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
 944         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
 945         (fs_ctx->export_flags & V9FS_SM_NONE)) {
 946         buffer = rpath(fs_ctx, path);
 947         ret = lchown(buffer, credp->fc_uid, credp->fc_gid);
 948         g_free(buffer);
 949     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
 950         buffer = rpath(fs_ctx, path);
 951         ret = local_set_xattr(buffer, credp);
 952         g_free(buffer);
 953     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 954         return local_set_mapped_file_attr(fs_ctx, path, credp);
 955     }
 956     return ret;
 957 }
 958
 959 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
 960                            const struct timespec *buf)
 961 {
 962     char *buffer;
 963     int ret;
 964     char *path = fs_path->data;
 965
 966     buffer = rpath(s, path);
 967     ret = qemu_utimens(buffer, buf);
 968     g_free(buffer);
 969     return ret;
 970 }
 971
 972 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
 973                                  int flags)
 974 {
 975     int ret = -1;
 976
 977     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 978         int map_dirfd;
 979
 980         if (flags == AT_REMOVEDIR) {
 981             int fd;
 982
 983             fd = openat(dirfd, name, O_RDONLY | O_DIRECTORY | O_PATH);
 984             if (fd == -1) {
 985                 goto err_out;
 986             }
 987             /*
 988              * If directory remove .virtfs_metadata contained in the
 989              * directory
 990              */
 991             ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
 992             close_preserve_errno(fd);
 993             if (ret < 0 && errno != ENOENT) {
 994                 /*
 995                  * We didn't had the .virtfs_metadata file. May be file created
 996                  * in non-mapped mode ?. Ignore ENOENT.
 997                  */
 998                 goto err_out;
 999             }
1000         }
1001         /*
1002          * Now remove the name from parent directory
1003          * .virtfs_metadata directory.
1004          */
1005         map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
1006         ret = unlinkat(map_dirfd, name, 0);
1007         close_preserve_errno(map_dirfd);
1008         if (ret < 0 && errno != ENOENT) {
1009             /*
1010              * We didn't had the .virtfs_metadata file. May be file created
1011              * in non-mapped mode ?. Ignore ENOENT.
1012              */
1013             goto err_out;
1014         }
1015     }
1016
1017     ret = unlinkat(dirfd, name, flags);
1018 err_out:
1019     return ret;
1020 }
1021
1022 static int local_remove(FsContext *ctx, const char *path)
1023 {
1024     struct stat stbuf;
1025     char *dirpath = g_path_get_dirname(path);
1026     char *name = g_path_get_basename(path);
1027     int flags = 0;
1028     int dirfd;
1029     int err = -1;
1030
1031     dirfd = local_opendir_nofollow(ctx, dirpath);
1032     if (dirfd) {
1033         goto out;
1034     }
1035
1036     if (fstatat(dirfd, path, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) {
1037         goto err_out;
1038     }
1039
1040     if (S_ISDIR(stbuf.st_mode)) {
1041         flags |= AT_REMOVEDIR;
1042     }
1043
1044     err = local_unlinkat_common(ctx, dirfd, name, flags);
1045 err_out:
1046     close_preserve_errno(dirfd);
1047 out:
1048     g_free(name);
1049     g_free(dirpath);
1050     return err;
1051 }
1052
1053 static int local_fsync(FsContext *ctx, int fid_type,
1054                        V9fsFidOpenState *fs, int datasync)
1055 {
1056     int fd;
1057
1058     if (fid_type == P9_FID_DIR) {
1059         fd = dirfd(fs->dir.stream);
1060     } else {
1061         fd = fs->fd;
1062     }
1063
1064     if (datasync) {
1065         return qemu_fdatasync(fd);
1066     } else {
1067         return fsync(fd);
1068     }
1069 }
1070
1071 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
1072 {
1073     char *buffer;
1074     int ret;
1075     char *path = fs_path->data;
1076
1077     buffer = rpath(s, path);
1078     ret = statfs(buffer, stbuf);
1079     g_free(buffer);
1080     return ret;
1081 }
1082
1083 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
1084                                const char *name, void *value, size_t size)
1085 {
1086     char *path = fs_path->data;
1087
1088     return v9fs_get_xattr(ctx, path, name, value, size);
1089 }
1090
1091 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path,
1092                                 void *value, size_t size)
1093 {
1094     char *path = fs_path->data;
1095
1096     return v9fs_list_xattr(ctx, path, value, size);
1097 }
1098
1099 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
1100                            void *value, size_t size, int flags)
1101 {
1102     char *path = fs_path->data;
1103
1104     return v9fs_set_xattr(ctx, path, name, value, size, flags);
1105 }
1106
1107 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
1108                               const char *name)
1109 {
1110     char *path = fs_path->data;
1111
1112     return v9fs_remove_xattr(ctx, path, name);
1113 }
1114
1115 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path,
1116                               const char *name, V9fsPath *target)
1117 {
1118     if (dir_path) {
1119         v9fs_path_sprintf(target, "%s/%s", dir_path->data, name);
1120     } else {
1121         v9fs_path_sprintf(target, "%s", name);
1122     }
1123     return 0;
1124 }
1125
1126 static int local_renameat(FsContext *ctx, V9fsPath *olddir,
1127                           const char *old_name, V9fsPath *newdir,
1128                           const char *new_name)
1129 {
1130     int ret;
1131     V9fsString old_full_name, new_full_name;
1132
1133     v9fs_string_init(&old_full_name);
1134     v9fs_string_init(&new_full_name);
1135
1136     v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
1137     v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
1138
1139     ret = local_rename(ctx, old_full_name.data, new_full_name.data);
1140     v9fs_string_free(&old_full_name);
1141     v9fs_string_free(&new_full_name);
1142     return ret;
1143 }
1144
1145 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
1146                           const char *name, int flags)
1147 {
1148     int ret;
1149     int dirfd;
1150
1151     dirfd = local_opendir_nofollow(ctx, dir->data);
1152     if (dirfd == -1) {
1153         return -1;
1154     }
1155
1156     ret = local_unlinkat_common(ctx, dirfd, name, flags);
1157     close_preserve_errno(dirfd);
1158     return ret;
1159 }
1160
1161 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
1162                                 mode_t st_mode, uint64_t *st_gen)
1163 {
1164 #ifdef FS_IOC_GETVERSION
1165     int err;
1166     V9fsFidOpenState fid_open;
1167
1168     /*
1169      * Do not try to open special files like device nodes, fifos etc
1170      * We can get fd for regular files and directories only
1171      */
1172     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
1173         errno = ENOTTY;
1174         return -1;
1175     }
1176     err = local_open(ctx, path, O_RDONLY, &fid_open);
1177     if (err < 0) {
1178         return err;
1179     }
1180     err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
1181     local_close(ctx, &fid_open);
1182     return err;
1183 #else
1184     errno = ENOTTY;
1185     return -1;
1186 #endif
1187 }
1188
1189 static int local_init(FsContext *ctx)
1190 {
1191     struct statfs stbuf;
1192     LocalData *data = g_malloc(sizeof(*data));
1193
1194     data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
1195     if (data->mountfd == -1) {
1196         goto err;
1197     }
1198
1199 #ifdef FS_IOC_GETVERSION
1200     /*
1201      * use ioc_getversion only if the ioctl is definied
1202      */
1203     if (fstatfs(data->mountfd, &stbuf) < 0) {
1204         close_preserve_errno(data->mountfd);
1205         goto err;
1206     }
1207     switch (stbuf.f_type) {
1208     case EXT2_SUPER_MAGIC:
1209     case BTRFS_SUPER_MAGIC:
1210     case REISERFS_SUPER_MAGIC:
1211     case XFS_SUPER_MAGIC:
1212         ctx->exops.get_st_gen = local_ioc_getversion;
1213         break;
1214     }
1215 #endif
1216
1217     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
1218         ctx->xops = passthrough_xattr_ops;
1219     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
1220         ctx->xops = mapped_xattr_ops;
1221     } else if (ctx->export_flags & V9FS_SM_NONE) {
1222         ctx->xops = none_xattr_ops;
1223     } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
1224         /*
1225          * xattr operation for mapped-file and passthrough
1226          * remain same.
1227          */
1228         ctx->xops = passthrough_xattr_ops;
1229     }
1230     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
1231
1232     ctx->private = data;
1233     return 0;
1234
1235 err:
1236     g_free(data);
1237     return -1;
1238 }
1239
1240 static void local_cleanup(FsContext *ctx)
1241 {
1242     LocalData *data = ctx->private;
1243
1244     close(data->mountfd);
1245     g_free(data);
1246 }
1247
1248 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
1249 {
1250     const char *sec_model = qemu_opt_get(opts, "security_model");
1251     const char *path = qemu_opt_get(opts, "path");
1252
1253     if (!sec_model) {
1254         error_report("Security model not specified, local fs needs security model");
1255         error_printf("valid options are:"
1256                      "\tsecurity_model=[passthrough|mapped-xattr|mapped-file|none]\n");
1257         return -1;
1258     }
1259
1260     if (!strcmp(sec_model, "passthrough")) {
1261         fse->export_flags |= V9FS_SM_PASSTHROUGH;
1262     } else if (!strcmp(sec_model, "mapped") ||
1263                !strcmp(sec_model, "mapped-xattr")) {
1264         fse->export_flags |= V9FS_SM_MAPPED;
1265     } else if (!strcmp(sec_model, "none")) {
1266         fse->export_flags |= V9FS_SM_NONE;
1267     } else if (!strcmp(sec_model, "mapped-file")) {
1268         fse->export_flags |= V9FS_SM_MAPPED_FILE;
1269     } else {
1270         error_report("Invalid security model %s specified", sec_model);
1271         error_printf("valid options are:"
1272                      "\t[passthrough|mapped-xattr|mapped-file|none]\n");
1273         return -1;
1274     }
1275
1276     if (!path) {
1277         error_report("fsdev: No path specified");
1278         return -1;
1279     }
1280     fse->path = g_strdup(path);
1281
1282     return 0;
1283 }
1284
1285 FileOperations local_ops = {
1286     .parse_opts = local_parse_opts,
1287     .init  = local_init,
1288     .cleanup = local_cleanup,
1289     .lstat = local_lstat,
1290     .readlink = local_readlink,
1291     .close = local_close,
1292     .closedir = local_closedir,
1293     .open = local_open,
1294     .opendir = local_opendir,
1295     .rewinddir = local_rewinddir,
1296     .telldir = local_telldir,
1297     .readdir = local_readdir,
1298     .seekdir = local_seekdir,
1299     .preadv = local_preadv,
1300     .pwritev = local_pwritev,
1301     .chmod = local_chmod,
1302     .mknod = local_mknod,
1303     .mkdir = local_mkdir,
1304     .fstat = local_fstat,
1305     .open2 = local_open2,
1306     .symlink = local_symlink,
1307     .link = local_link,
1308     .truncate = local_truncate,
1309     .rename = local_rename,
1310     .chown = local_chown,
1311     .utimensat = local_utimensat,
1312     .remove = local_remove,
1313     .fsync = local_fsync,
1314     .statfs = local_statfs,
1315     .lgetxattr = local_lgetxattr,
1316     .llistxattr = local_llistxattr,
1317     .lsetxattr = local_lsetxattr,
1318     .lremovexattr = local_lremovexattr,
1319     .name_to_path = local_name_to_path,
1320     .renameat  = local_renameat,
1321     .unlinkat = local_unlinkat,
1322 };