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 static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd, 71 const char *npath) 72 { 73 int serrno = errno; 74 renameat(odirfd, opath, ndirfd, npath); 75 errno = serrno; 76 } 77 78 static void unlinkat_preserve_errno(int dirfd, const char *path, int flags) 79 { 80 int serrno = errno; 81 unlinkat(dirfd, path, flags); 82 errno = serrno; 83 } 84 85 #define VIRTFS_META_DIR ".virtfs_metadata" 86 87 static FILE *local_fopenat(int dirfd, const char *name, const char *mode) 88 { 89 int fd, o_mode = 0; 90 FILE *fp; 91 int flags; 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 = openat_file(dirfd, name, 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(int dirfd, const char *name, 116 struct stat *stbuf) 117 { 118 FILE *fp; 119 char buf[ATTR_MAX]; 120 int map_dirfd; 121 122 map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); 123 if (map_dirfd == -1) { 124 return; 125 } 126 127 fp = local_fopenat(map_dirfd, name, "r"); 128 close_preserve_errno(map_dirfd); 129 if (!fp) { 130 return; 131 } 132 memset(buf, 0, ATTR_MAX); 133 while (fgets(buf, ATTR_MAX, fp)) { 134 if (!strncmp(buf, "virtfs.uid", 10)) { 135 stbuf->st_uid = atoi(buf+11); 136 } else if (!strncmp(buf, "virtfs.gid", 10)) { 137 stbuf->st_gid = atoi(buf+11); 138 } else if (!strncmp(buf, "virtfs.mode", 11)) { 139 stbuf->st_mode = atoi(buf+12); 140 } else if (!strncmp(buf, "virtfs.rdev", 11)) { 141 stbuf->st_rdev = atoi(buf+12); 142 } 143 memset(buf, 0, ATTR_MAX); 144 } 145 fclose(fp); 146 } 147 148 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf) 149 { 150 int err = -1; 151 char *dirpath = g_path_get_dirname(fs_path->data); 152 char *name = g_path_get_basename(fs_path->data); 153 int dirfd; 154 155 dirfd = local_opendir_nofollow(fs_ctx, dirpath); 156 if (dirfd == -1) { 157 goto out; 158 } 159 160 err = fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW); 161 if (err) { 162 goto err_out; 163 } 164 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 165 /* Actual credentials are part of extended attrs */ 166 uid_t tmp_uid; 167 gid_t tmp_gid; 168 mode_t tmp_mode; 169 dev_t tmp_dev; 170 171 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.uid", &tmp_uid, 172 sizeof(uid_t)) > 0) { 173 stbuf->st_uid = le32_to_cpu(tmp_uid); 174 } 175 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.gid", &tmp_gid, 176 sizeof(gid_t)) > 0) { 177 stbuf->st_gid = le32_to_cpu(tmp_gid); 178 } 179 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.mode", &tmp_mode, 180 sizeof(mode_t)) > 0) { 181 stbuf->st_mode = le32_to_cpu(tmp_mode); 182 } 183 if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.rdev", &tmp_dev, 184 sizeof(dev_t)) > 0) { 185 stbuf->st_rdev = le64_to_cpu(tmp_dev); 186 } 187 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 188 local_mapped_file_attr(dirfd, name, stbuf); 189 } 190 191 err_out: 192 close_preserve_errno(dirfd); 193 out: 194 g_free(name); 195 g_free(dirpath); 196 return err; 197 } 198 199 static int local_set_mapped_file_attrat(int dirfd, const char *name, 200 FsCred *credp) 201 { 202 FILE *fp; 203 int ret; 204 char buf[ATTR_MAX]; 205 int uid = -1, gid = -1, mode = -1, rdev = -1; 206 int map_dirfd; 207 208 ret = mkdirat(dirfd, VIRTFS_META_DIR, 0700); 209 if (ret < 0 && errno != EEXIST) { 210 return -1; 211 } 212 213 map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); 214 if (map_dirfd == -1) { 215 return -1; 216 } 217 218 fp = local_fopenat(map_dirfd, name, "r"); 219 if (!fp) { 220 if (errno == ENOENT) { 221 goto update_map_file; 222 } else { 223 close_preserve_errno(map_dirfd); 224 return -1; 225 } 226 } 227 memset(buf, 0, ATTR_MAX); 228 while (fgets(buf, ATTR_MAX, fp)) { 229 if (!strncmp(buf, "virtfs.uid", 10)) { 230 uid = atoi(buf + 11); 231 } else if (!strncmp(buf, "virtfs.gid", 10)) { 232 gid = atoi(buf + 11); 233 } else if (!strncmp(buf, "virtfs.mode", 11)) { 234 mode = atoi(buf + 12); 235 } else if (!strncmp(buf, "virtfs.rdev", 11)) { 236 rdev = atoi(buf + 12); 237 } 238 memset(buf, 0, ATTR_MAX); 239 } 240 fclose(fp); 241 242 update_map_file: 243 fp = local_fopenat(map_dirfd, name, "w"); 244 close_preserve_errno(map_dirfd); 245 if (!fp) { 246 return -1; 247 } 248 249 if (credp->fc_uid != -1) { 250 uid = credp->fc_uid; 251 } 252 if (credp->fc_gid != -1) { 253 gid = credp->fc_gid; 254 } 255 if (credp->fc_mode != -1) { 256 mode = credp->fc_mode; 257 } 258 if (credp->fc_rdev != -1) { 259 rdev = credp->fc_rdev; 260 } 261 262 if (uid != -1) { 263 fprintf(fp, "virtfs.uid=%d\n", uid); 264 } 265 if (gid != -1) { 266 fprintf(fp, "virtfs.gid=%d\n", gid); 267 } 268 if (mode != -1) { 269 fprintf(fp, "virtfs.mode=%d\n", mode); 270 } 271 if (rdev != -1) { 272 fprintf(fp, "virtfs.rdev=%d\n", rdev); 273 } 274 fclose(fp); 275 276 return 0; 277 } 278 279 static int fchmodat_nofollow(int dirfd, const char *name, mode_t mode) 280 { 281 int fd, ret; 282 283 /* FIXME: this should be handled with fchmodat(AT_SYMLINK_NOFOLLOW). 284 * Unfortunately, the linux kernel doesn't implement it yet. As an 285 * alternative, let's open the file and use fchmod() instead. This 286 * may fail depending on the permissions of the file, but it is the 287 * best we can do to avoid TOCTTOU. We first try to open read-only 288 * in case name points to a directory. If that fails, we try write-only 289 * in case name doesn't point to a directory. 290 */ 291 fd = openat_file(dirfd, name, O_RDONLY, 0); 292 if (fd == -1) { 293 /* In case the file is writable-only and isn't a directory. */ 294 if (errno == EACCES) { 295 fd = openat_file(dirfd, name, O_WRONLY, 0); 296 } 297 if (fd == -1 && errno == EISDIR) { 298 errno = EACCES; 299 } 300 } 301 if (fd == -1) { 302 return -1; 303 } 304 ret = fchmod(fd, mode); 305 close_preserve_errno(fd); 306 return ret; 307 } 308 309 static int local_set_xattrat(int dirfd, const char *path, FsCred *credp) 310 { 311 int err; 312 313 if (credp->fc_uid != -1) { 314 uint32_t tmp_uid = cpu_to_le32(credp->fc_uid); 315 err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.uid", &tmp_uid, 316 sizeof(uid_t), 0); 317 if (err) { 318 return err; 319 } 320 } 321 if (credp->fc_gid != -1) { 322 uint32_t tmp_gid = cpu_to_le32(credp->fc_gid); 323 err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.gid", &tmp_gid, 324 sizeof(gid_t), 0); 325 if (err) { 326 return err; 327 } 328 } 329 if (credp->fc_mode != -1) { 330 uint32_t tmp_mode = cpu_to_le32(credp->fc_mode); 331 err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.mode", &tmp_mode, 332 sizeof(mode_t), 0); 333 if (err) { 334 return err; 335 } 336 } 337 if (credp->fc_rdev != -1) { 338 uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev); 339 err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.rdev", &tmp_rdev, 340 sizeof(dev_t), 0); 341 if (err) { 342 return err; 343 } 344 } 345 return 0; 346 } 347 348 static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd, 349 const char *name, FsCred *credp) 350 { 351 if (fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, 352 AT_SYMLINK_NOFOLLOW) < 0) { 353 /* 354 * If we fail to change ownership and if we are 355 * using security model none. Ignore the error 356 */ 357 if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) { 358 return -1; 359 } 360 } 361 362 return fchmodat_nofollow(dirfd, name, credp->fc_mode & 07777); 363 } 364 365 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path, 366 char *buf, size_t bufsz) 367 { 368 ssize_t tsize = -1; 369 370 if ((fs_ctx->export_flags & V9FS_SM_MAPPED) || 371 (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) { 372 int fd; 373 374 fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0); 375 if (fd == -1) { 376 return -1; 377 } 378 do { 379 tsize = read(fd, (void *)buf, bufsz); 380 } while (tsize == -1 && errno == EINTR); 381 close_preserve_errno(fd); 382 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || 383 (fs_ctx->export_flags & V9FS_SM_NONE)) { 384 char *dirpath = g_path_get_dirname(fs_path->data); 385 char *name = g_path_get_basename(fs_path->data); 386 int dirfd; 387 388 dirfd = local_opendir_nofollow(fs_ctx, dirpath); 389 if (dirfd == -1) { 390 goto out; 391 } 392 393 tsize = readlinkat(dirfd, name, buf, bufsz); 394 close_preserve_errno(dirfd); 395 out: 396 g_free(name); 397 g_free(dirpath); 398 } 399 return tsize; 400 } 401 402 static int local_close(FsContext *ctx, V9fsFidOpenState *fs) 403 { 404 return close(fs->fd); 405 } 406 407 static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs) 408 { 409 return closedir(fs->dir.stream); 410 } 411 412 static int local_open(FsContext *ctx, V9fsPath *fs_path, 413 int flags, V9fsFidOpenState *fs) 414 { 415 int fd; 416 417 fd = local_open_nofollow(ctx, fs_path->data, flags, 0); 418 if (fd == -1) { 419 return -1; 420 } 421 fs->fd = fd; 422 return fs->fd; 423 } 424 425 static int local_opendir(FsContext *ctx, 426 V9fsPath *fs_path, V9fsFidOpenState *fs) 427 { 428 int dirfd; 429 DIR *stream; 430 431 dirfd = local_opendir_nofollow(ctx, fs_path->data); 432 if (dirfd == -1) { 433 return -1; 434 } 435 436 stream = fdopendir(dirfd); 437 if (!stream) { 438 close(dirfd); 439 return -1; 440 } 441 fs->dir.stream = stream; 442 return 0; 443 } 444 445 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) 446 { 447 rewinddir(fs->dir.stream); 448 } 449 450 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs) 451 { 452 return telldir(fs->dir.stream); 453 } 454 455 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs) 456 { 457 struct dirent *entry; 458 459 again: 460 entry = readdir(fs->dir.stream); 461 if (!entry) { 462 return NULL; 463 } 464 465 if (ctx->export_flags & V9FS_SM_MAPPED) { 466 entry->d_type = DT_UNKNOWN; 467 } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 468 if (!strcmp(entry->d_name, VIRTFS_META_DIR)) { 469 /* skp the meta data directory */ 470 goto again; 471 } 472 entry->d_type = DT_UNKNOWN; 473 } 474 475 return entry; 476 } 477 478 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) 479 { 480 seekdir(fs->dir.stream, off); 481 } 482 483 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs, 484 const struct iovec *iov, 485 int iovcnt, off_t offset) 486 { 487 #ifdef CONFIG_PREADV 488 return preadv(fs->fd, iov, iovcnt, offset); 489 #else 490 int err = lseek(fs->fd, offset, SEEK_SET); 491 if (err == -1) { 492 return err; 493 } else { 494 return readv(fs->fd, iov, iovcnt); 495 } 496 #endif 497 } 498 499 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs, 500 const struct iovec *iov, 501 int iovcnt, off_t offset) 502 { 503 ssize_t ret; 504 #ifdef CONFIG_PREADV 505 ret = pwritev(fs->fd, iov, iovcnt, offset); 506 #else 507 int err = lseek(fs->fd, offset, SEEK_SET); 508 if (err == -1) { 509 return err; 510 } else { 511 ret = writev(fs->fd, iov, iovcnt); 512 } 513 #endif 514 #ifdef CONFIG_SYNC_FILE_RANGE 515 if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) { 516 /* 517 * Initiate a writeback. This is not a data integrity sync. 518 * We want to ensure that we don't leave dirty pages in the cache 519 * after write when writeout=immediate is sepcified. 520 */ 521 sync_file_range(fs->fd, offset, ret, 522 SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE); 523 } 524 #endif 525 return ret; 526 } 527 528 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) 529 { 530 char *dirpath = g_path_get_dirname(fs_path->data); 531 char *name = g_path_get_basename(fs_path->data); 532 int ret = -1; 533 int dirfd; 534 535 dirfd = local_opendir_nofollow(fs_ctx, dirpath); 536 if (dirfd == -1) { 537 goto out; 538 } 539 540 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 541 ret = local_set_xattrat(dirfd, name, credp); 542 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 543 ret = local_set_mapped_file_attrat(dirfd, name, credp); 544 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 545 fs_ctx->export_flags & V9FS_SM_NONE) { 546 ret = fchmodat_nofollow(dirfd, name, credp->fc_mode); 547 } 548 close_preserve_errno(dirfd); 549 550 out: 551 g_free(dirpath); 552 g_free(name); 553 return ret; 554 } 555 556 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path, 557 const char *name, FsCred *credp) 558 { 559 int err = -1; 560 int dirfd; 561 562 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 563 if (dirfd == -1) { 564 return -1; 565 } 566 567 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 568 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 569 err = mknodat(dirfd, name, SM_LOCAL_MODE_BITS | S_IFREG, 0); 570 if (err == -1) { 571 goto out; 572 } 573 574 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 575 err = local_set_xattrat(dirfd, name, credp); 576 } else { 577 err = local_set_mapped_file_attrat(dirfd, name, credp); 578 } 579 if (err == -1) { 580 goto err_end; 581 } 582 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 583 fs_ctx->export_flags & V9FS_SM_NONE) { 584 err = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev); 585 if (err == -1) { 586 goto out; 587 } 588 err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); 589 if (err == -1) { 590 goto err_end; 591 } 592 } 593 goto out; 594 595 err_end: 596 unlinkat_preserve_errno(dirfd, name, 0); 597 out: 598 close_preserve_errno(dirfd); 599 return err; 600 } 601 602 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path, 603 const char *name, FsCred *credp) 604 { 605 int err = -1; 606 int dirfd; 607 608 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 609 if (dirfd == -1) { 610 return -1; 611 } 612 613 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 614 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 615 err = mkdirat(dirfd, name, SM_LOCAL_DIR_MODE_BITS); 616 if (err == -1) { 617 goto out; 618 } 619 credp->fc_mode = credp->fc_mode | S_IFDIR; 620 621 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 622 err = local_set_xattrat(dirfd, name, credp); 623 } else { 624 err = local_set_mapped_file_attrat(dirfd, name, credp); 625 } 626 if (err == -1) { 627 goto err_end; 628 } 629 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 630 fs_ctx->export_flags & V9FS_SM_NONE) { 631 err = mkdirat(dirfd, name, credp->fc_mode); 632 if (err == -1) { 633 goto out; 634 } 635 err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); 636 if (err == -1) { 637 goto err_end; 638 } 639 } 640 goto out; 641 642 err_end: 643 unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR); 644 out: 645 close_preserve_errno(dirfd); 646 return err; 647 } 648 649 static int local_fstat(FsContext *fs_ctx, int fid_type, 650 V9fsFidOpenState *fs, struct stat *stbuf) 651 { 652 int err, fd; 653 654 if (fid_type == P9_FID_DIR) { 655 fd = dirfd(fs->dir.stream); 656 } else { 657 fd = fs->fd; 658 } 659 660 err = fstat(fd, stbuf); 661 if (err) { 662 return err; 663 } 664 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 665 /* Actual credentials are part of extended attrs */ 666 uid_t tmp_uid; 667 gid_t tmp_gid; 668 mode_t tmp_mode; 669 dev_t tmp_dev; 670 671 if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) { 672 stbuf->st_uid = le32_to_cpu(tmp_uid); 673 } 674 if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) { 675 stbuf->st_gid = le32_to_cpu(tmp_gid); 676 } 677 if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) { 678 stbuf->st_mode = le32_to_cpu(tmp_mode); 679 } 680 if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) { 681 stbuf->st_rdev = le64_to_cpu(tmp_dev); 682 } 683 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 684 errno = EOPNOTSUPP; 685 return -1; 686 } 687 return err; 688 } 689 690 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, 691 int flags, FsCred *credp, V9fsFidOpenState *fs) 692 { 693 int fd = -1; 694 int err = -1; 695 int dirfd; 696 697 /* 698 * Mark all the open to not follow symlinks 699 */ 700 flags |= O_NOFOLLOW; 701 702 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 703 if (dirfd == -1) { 704 return -1; 705 } 706 707 /* Determine the security model */ 708 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 709 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 710 fd = openat_file(dirfd, name, flags, SM_LOCAL_MODE_BITS); 711 if (fd == -1) { 712 goto out; 713 } 714 credp->fc_mode = credp->fc_mode|S_IFREG; 715 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 716 /* Set cleint credentials in xattr */ 717 err = local_set_xattrat(dirfd, name, credp); 718 } else { 719 err = local_set_mapped_file_attrat(dirfd, name, credp); 720 } 721 if (err == -1) { 722 goto err_end; 723 } 724 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || 725 (fs_ctx->export_flags & V9FS_SM_NONE)) { 726 fd = openat_file(dirfd, name, flags, credp->fc_mode); 727 if (fd == -1) { 728 goto out; 729 } 730 err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); 731 if (err == -1) { 732 goto err_end; 733 } 734 } 735 err = fd; 736 fs->fd = fd; 737 goto out; 738 739 err_end: 740 unlinkat_preserve_errno(dirfd, name, 741 flags & O_DIRECTORY ? AT_REMOVEDIR : 0); 742 close_preserve_errno(fd); 743 out: 744 close_preserve_errno(dirfd); 745 return err; 746 } 747 748 749 static int local_symlink(FsContext *fs_ctx, const char *oldpath, 750 V9fsPath *dir_path, const char *name, FsCred *credp) 751 { 752 int err = -1; 753 int dirfd; 754 755 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 756 if (dirfd == -1) { 757 return -1; 758 } 759 760 /* Determine the security model */ 761 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 762 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 763 int fd; 764 ssize_t oldpath_size, write_size; 765 766 fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR, 767 SM_LOCAL_MODE_BITS); 768 if (fd == -1) { 769 goto out; 770 } 771 /* Write the oldpath (target) to the file. */ 772 oldpath_size = strlen(oldpath); 773 do { 774 write_size = write(fd, (void *)oldpath, oldpath_size); 775 } while (write_size == -1 && errno == EINTR); 776 close_preserve_errno(fd); 777 778 if (write_size != oldpath_size) { 779 goto err_end; 780 } 781 /* Set cleint credentials in symlink's xattr */ 782 credp->fc_mode = credp->fc_mode | S_IFLNK; 783 784 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 785 err = local_set_xattrat(dirfd, name, credp); 786 } else { 787 err = local_set_mapped_file_attrat(dirfd, name, credp); 788 } 789 if (err == -1) { 790 goto err_end; 791 } 792 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 793 fs_ctx->export_flags & V9FS_SM_NONE) { 794 err = symlinkat(oldpath, dirfd, name); 795 if (err) { 796 goto out; 797 } 798 err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, 799 AT_SYMLINK_NOFOLLOW); 800 if (err == -1) { 801 /* 802 * If we fail to change ownership and if we are 803 * using security model none. Ignore the error 804 */ 805 if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) { 806 goto err_end; 807 } else { 808 err = 0; 809 } 810 } 811 } 812 goto out; 813 814 err_end: 815 unlinkat_preserve_errno(dirfd, name, 0); 816 out: 817 close_preserve_errno(dirfd); 818 return err; 819 } 820 821 static int local_link(FsContext *ctx, V9fsPath *oldpath, 822 V9fsPath *dirpath, const char *name) 823 { 824 char *odirpath = g_path_get_dirname(oldpath->data); 825 char *oname = g_path_get_basename(oldpath->data); 826 int ret = -1; 827 int odirfd, ndirfd; 828 829 odirfd = local_opendir_nofollow(ctx, odirpath); 830 if (odirfd == -1) { 831 goto out; 832 } 833 834 ndirfd = local_opendir_nofollow(ctx, dirpath->data); 835 if (ndirfd == -1) { 836 close_preserve_errno(odirfd); 837 goto out; 838 } 839 840 ret = linkat(odirfd, oname, ndirfd, name, 0); 841 if (ret < 0) { 842 goto out_close; 843 } 844 845 /* now link the virtfs_metadata files */ 846 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 847 int omap_dirfd, nmap_dirfd; 848 849 ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700); 850 if (ret < 0 && errno != EEXIST) { 851 goto err_undo_link; 852 } 853 854 omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR); 855 if (omap_dirfd == -1) { 856 goto err; 857 } 858 859 nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR); 860 if (nmap_dirfd == -1) { 861 close_preserve_errno(omap_dirfd); 862 goto err; 863 } 864 865 ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0); 866 close_preserve_errno(nmap_dirfd); 867 close_preserve_errno(omap_dirfd); 868 if (ret < 0 && errno != ENOENT) { 869 goto err_undo_link; 870 } 871 872 ret = 0; 873 } 874 goto out_close; 875 876 err: 877 ret = -1; 878 err_undo_link: 879 unlinkat_preserve_errno(ndirfd, name, 0); 880 out_close: 881 close_preserve_errno(ndirfd); 882 close_preserve_errno(odirfd); 883 out: 884 g_free(oname); 885 g_free(odirpath); 886 return ret; 887 } 888 889 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size) 890 { 891 int fd, ret; 892 893 fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0); 894 if (fd == -1) { 895 return -1; 896 } 897 ret = ftruncate(fd, size); 898 close_preserve_errno(fd); 899 return ret; 900 } 901 902 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) 903 { 904 char *dirpath = g_path_get_dirname(fs_path->data); 905 char *name = g_path_get_basename(fs_path->data); 906 int ret = -1; 907 int dirfd; 908 909 dirfd = local_opendir_nofollow(fs_ctx, dirpath); 910 if (dirfd == -1) { 911 goto out; 912 } 913 914 if ((credp->fc_uid == -1 && credp->fc_gid == -1) || 915 (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || 916 (fs_ctx->export_flags & V9FS_SM_NONE)) { 917 ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, 918 AT_SYMLINK_NOFOLLOW); 919 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 920 ret = local_set_xattrat(dirfd, name, credp); 921 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 922 ret = local_set_mapped_file_attrat(dirfd, name, credp); 923 } 924 925 close_preserve_errno(dirfd); 926 out: 927 g_free(name); 928 g_free(dirpath); 929 return ret; 930 } 931 932 static int local_utimensat(FsContext *s, V9fsPath *fs_path, 933 const struct timespec *buf) 934 { 935 char *dirpath = g_path_get_dirname(fs_path->data); 936 char *name = g_path_get_basename(fs_path->data); 937 int dirfd, ret = -1; 938 939 dirfd = local_opendir_nofollow(s, dirpath); 940 if (dirfd == -1) { 941 goto out; 942 } 943 944 ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW); 945 close_preserve_errno(dirfd); 946 out: 947 g_free(dirpath); 948 g_free(name); 949 return ret; 950 } 951 952 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, 953 int flags) 954 { 955 int ret = -1; 956 957 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 958 int map_dirfd; 959 960 if (flags == AT_REMOVEDIR) { 961 int fd; 962 963 fd = openat_dir(dirfd, name); 964 if (fd == -1) { 965 goto err_out; 966 } 967 /* 968 * If directory remove .virtfs_metadata contained in the 969 * directory 970 */ 971 ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR); 972 close_preserve_errno(fd); 973 if (ret < 0 && errno != ENOENT) { 974 /* 975 * We didn't had the .virtfs_metadata file. May be file created 976 * in non-mapped mode ?. Ignore ENOENT. 977 */ 978 goto err_out; 979 } 980 } 981 /* 982 * Now remove the name from parent directory 983 * .virtfs_metadata directory. 984 */ 985 map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); 986 ret = unlinkat(map_dirfd, name, 0); 987 close_preserve_errno(map_dirfd); 988 if (ret < 0 && errno != ENOENT) { 989 /* 990 * We didn't had the .virtfs_metadata file. May be file created 991 * in non-mapped mode ?. Ignore ENOENT. 992 */ 993 goto err_out; 994 } 995 } 996 997 ret = unlinkat(dirfd, name, flags); 998 err_out: 999 return ret; 1000 } 1001 1002 static int local_remove(FsContext *ctx, const char *path) 1003 { 1004 struct stat stbuf; 1005 char *dirpath = g_path_get_dirname(path); 1006 char *name = g_path_get_basename(path); 1007 int flags = 0; 1008 int dirfd; 1009 int err = -1; 1010 1011 dirfd = local_opendir_nofollow(ctx, dirpath); 1012 if (dirfd == -1) { 1013 goto out; 1014 } 1015 1016 if (fstatat(dirfd, path, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) { 1017 goto err_out; 1018 } 1019 1020 if (S_ISDIR(stbuf.st_mode)) { 1021 flags |= AT_REMOVEDIR; 1022 } 1023 1024 err = local_unlinkat_common(ctx, dirfd, name, flags); 1025 err_out: 1026 close_preserve_errno(dirfd); 1027 out: 1028 g_free(name); 1029 g_free(dirpath); 1030 return err; 1031 } 1032 1033 static int local_fsync(FsContext *ctx, int fid_type, 1034 V9fsFidOpenState *fs, int datasync) 1035 { 1036 int fd; 1037 1038 if (fid_type == P9_FID_DIR) { 1039 fd = dirfd(fs->dir.stream); 1040 } else { 1041 fd = fs->fd; 1042 } 1043 1044 if (datasync) { 1045 return qemu_fdatasync(fd); 1046 } else { 1047 return fsync(fd); 1048 } 1049 } 1050 1051 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) 1052 { 1053 int fd, ret; 1054 1055 fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0); 1056 if (fd == -1) { 1057 return -1; 1058 } 1059 ret = fstatfs(fd, stbuf); 1060 close_preserve_errno(fd); 1061 return ret; 1062 } 1063 1064 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path, 1065 const char *name, void *value, size_t size) 1066 { 1067 char *path = fs_path->data; 1068 1069 return v9fs_get_xattr(ctx, path, name, value, size); 1070 } 1071 1072 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path, 1073 void *value, size_t size) 1074 { 1075 char *path = fs_path->data; 1076 1077 return v9fs_list_xattr(ctx, path, value, size); 1078 } 1079 1080 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name, 1081 void *value, size_t size, int flags) 1082 { 1083 char *path = fs_path->data; 1084 1085 return v9fs_set_xattr(ctx, path, name, value, size, flags); 1086 } 1087 1088 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path, 1089 const char *name) 1090 { 1091 char *path = fs_path->data; 1092 1093 return v9fs_remove_xattr(ctx, path, name); 1094 } 1095 1096 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path, 1097 const char *name, V9fsPath *target) 1098 { 1099 if (dir_path) { 1100 v9fs_path_sprintf(target, "%s/%s", dir_path->data, name); 1101 } else { 1102 v9fs_path_sprintf(target, "%s", name); 1103 } 1104 return 0; 1105 } 1106 1107 static int local_renameat(FsContext *ctx, V9fsPath *olddir, 1108 const char *old_name, V9fsPath *newdir, 1109 const char *new_name) 1110 { 1111 int ret; 1112 int odirfd, ndirfd; 1113 1114 odirfd = local_opendir_nofollow(ctx, olddir->data); 1115 if (odirfd == -1) { 1116 return -1; 1117 } 1118 1119 ndirfd = local_opendir_nofollow(ctx, newdir->data); 1120 if (ndirfd == -1) { 1121 close_preserve_errno(odirfd); 1122 return -1; 1123 } 1124 1125 ret = renameat(odirfd, old_name, ndirfd, new_name); 1126 if (ret < 0) { 1127 goto out; 1128 } 1129 1130 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 1131 int omap_dirfd, nmap_dirfd; 1132 1133 ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700); 1134 if (ret < 0 && errno != EEXIST) { 1135 goto err_undo_rename; 1136 } 1137 1138 omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR); 1139 if (omap_dirfd == -1) { 1140 goto err; 1141 } 1142 1143 nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR); 1144 if (nmap_dirfd == -1) { 1145 close_preserve_errno(omap_dirfd); 1146 goto err; 1147 } 1148 1149 /* rename the .virtfs_metadata files */ 1150 ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name); 1151 close_preserve_errno(nmap_dirfd); 1152 close_preserve_errno(omap_dirfd); 1153 if (ret < 0 && errno != ENOENT) { 1154 goto err_undo_rename; 1155 } 1156 1157 ret = 0; 1158 } 1159 goto out; 1160 1161 err: 1162 ret = -1; 1163 err_undo_rename: 1164 renameat_preserve_errno(ndirfd, new_name, odirfd, old_name); 1165 out: 1166 close_preserve_errno(ndirfd); 1167 close_preserve_errno(odirfd); 1168 return ret; 1169 } 1170 1171 static void v9fs_path_init_dirname(V9fsPath *path, const char *str) 1172 { 1173 path->data = g_path_get_dirname(str); 1174 path->size = strlen(path->data) + 1; 1175 } 1176 1177 static int local_rename(FsContext *ctx, const char *oldpath, 1178 const char *newpath) 1179 { 1180 int err; 1181 char *oname = g_path_get_basename(oldpath); 1182 char *nname = g_path_get_basename(newpath); 1183 V9fsPath olddir, newdir; 1184 1185 v9fs_path_init_dirname(&olddir, oldpath); 1186 v9fs_path_init_dirname(&newdir, newpath); 1187 1188 err = local_renameat(ctx, &olddir, oname, &newdir, nname); 1189 1190 v9fs_path_free(&newdir); 1191 v9fs_path_free(&olddir); 1192 g_free(nname); 1193 g_free(oname); 1194 1195 return err; 1196 } 1197 1198 static int local_unlinkat(FsContext *ctx, V9fsPath *dir, 1199 const char *name, int flags) 1200 { 1201 int ret; 1202 int dirfd; 1203 1204 dirfd = local_opendir_nofollow(ctx, dir->data); 1205 if (dirfd == -1) { 1206 return -1; 1207 } 1208 1209 ret = local_unlinkat_common(ctx, dirfd, name, flags); 1210 close_preserve_errno(dirfd); 1211 return ret; 1212 } 1213 1214 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path, 1215 mode_t st_mode, uint64_t *st_gen) 1216 { 1217 #ifdef FS_IOC_GETVERSION 1218 int err; 1219 V9fsFidOpenState fid_open; 1220 1221 /* 1222 * Do not try to open special files like device nodes, fifos etc 1223 * We can get fd for regular files and directories only 1224 */ 1225 if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) { 1226 errno = ENOTTY; 1227 return -1; 1228 } 1229 err = local_open(ctx, path, O_RDONLY, &fid_open); 1230 if (err < 0) { 1231 return err; 1232 } 1233 err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen); 1234 local_close(ctx, &fid_open); 1235 return err; 1236 #else 1237 errno = ENOTTY; 1238 return -1; 1239 #endif 1240 } 1241 1242 static int local_init(FsContext *ctx) 1243 { 1244 struct statfs stbuf; 1245 LocalData *data = g_malloc(sizeof(*data)); 1246 1247 data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY); 1248 if (data->mountfd == -1) { 1249 goto err; 1250 } 1251 1252 #ifdef FS_IOC_GETVERSION 1253 /* 1254 * use ioc_getversion only if the ioctl is definied 1255 */ 1256 if (fstatfs(data->mountfd, &stbuf) < 0) { 1257 close_preserve_errno(data->mountfd); 1258 goto err; 1259 } 1260 switch (stbuf.f_type) { 1261 case EXT2_SUPER_MAGIC: 1262 case BTRFS_SUPER_MAGIC: 1263 case REISERFS_SUPER_MAGIC: 1264 case XFS_SUPER_MAGIC: 1265 ctx->exops.get_st_gen = local_ioc_getversion; 1266 break; 1267 } 1268 #endif 1269 1270 if (ctx->export_flags & V9FS_SM_PASSTHROUGH) { 1271 ctx->xops = passthrough_xattr_ops; 1272 } else if (ctx->export_flags & V9FS_SM_MAPPED) { 1273 ctx->xops = mapped_xattr_ops; 1274 } else if (ctx->export_flags & V9FS_SM_NONE) { 1275 ctx->xops = none_xattr_ops; 1276 } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 1277 /* 1278 * xattr operation for mapped-file and passthrough 1279 * remain same. 1280 */ 1281 ctx->xops = passthrough_xattr_ops; 1282 } 1283 ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT; 1284 1285 ctx->private = data; 1286 return 0; 1287 1288 err: 1289 g_free(data); 1290 return -1; 1291 } 1292 1293 static void local_cleanup(FsContext *ctx) 1294 { 1295 LocalData *data = ctx->private; 1296 1297 close(data->mountfd); 1298 g_free(data); 1299 } 1300 1301 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse) 1302 { 1303 const char *sec_model = qemu_opt_get(opts, "security_model"); 1304 const char *path = qemu_opt_get(opts, "path"); 1305 Error *err = NULL; 1306 1307 if (!sec_model) { 1308 error_report("Security model not specified, local fs needs security model"); 1309 error_printf("valid options are:" 1310 "\tsecurity_model=[passthrough|mapped-xattr|mapped-file|none]\n"); 1311 return -1; 1312 } 1313 1314 if (!strcmp(sec_model, "passthrough")) { 1315 fse->export_flags |= V9FS_SM_PASSTHROUGH; 1316 } else if (!strcmp(sec_model, "mapped") || 1317 !strcmp(sec_model, "mapped-xattr")) { 1318 fse->export_flags |= V9FS_SM_MAPPED; 1319 } else if (!strcmp(sec_model, "none")) { 1320 fse->export_flags |= V9FS_SM_NONE; 1321 } else if (!strcmp(sec_model, "mapped-file")) { 1322 fse->export_flags |= V9FS_SM_MAPPED_FILE; 1323 } else { 1324 error_report("Invalid security model %s specified", sec_model); 1325 error_printf("valid options are:" 1326 "\t[passthrough|mapped-xattr|mapped-file|none]\n"); 1327 return -1; 1328 } 1329 1330 if (!path) { 1331 error_report("fsdev: No path specified"); 1332 return -1; 1333 } 1334 1335 fsdev_throttle_parse_opts(opts, &fse->fst, &err); 1336 if (err) { 1337 error_reportf_err(err, "Throttle configuration is not valid: "); 1338 return -1; 1339 } 1340 1341 fse->path = g_strdup(path); 1342 1343 return 0; 1344 } 1345 1346 FileOperations local_ops = { 1347 .parse_opts = local_parse_opts, 1348 .init = local_init, 1349 .cleanup = local_cleanup, 1350 .lstat = local_lstat, 1351 .readlink = local_readlink, 1352 .close = local_close, 1353 .closedir = local_closedir, 1354 .open = local_open, 1355 .opendir = local_opendir, 1356 .rewinddir = local_rewinddir, 1357 .telldir = local_telldir, 1358 .readdir = local_readdir, 1359 .seekdir = local_seekdir, 1360 .preadv = local_preadv, 1361 .pwritev = local_pwritev, 1362 .chmod = local_chmod, 1363 .mknod = local_mknod, 1364 .mkdir = local_mkdir, 1365 .fstat = local_fstat, 1366 .open2 = local_open2, 1367 .symlink = local_symlink, 1368 .link = local_link, 1369 .truncate = local_truncate, 1370 .rename = local_rename, 1371 .chown = local_chown, 1372 .utimensat = local_utimensat, 1373 .remove = local_remove, 1374 .fsync = local_fsync, 1375 .statfs = local_statfs, 1376 .lgetxattr = local_lgetxattr, 1377 .llistxattr = local_llistxattr, 1378 .lsetxattr = local_lsetxattr, 1379 .lremovexattr = local_lremovexattr, 1380 .name_to_path = local_name_to_path, 1381 .renameat = local_renameat, 1382 .unlinkat = local_unlinkat, 1383 }; 1384