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 | AT_EMPTY_PATH) < 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 return -1; 439 } 440 fs->dir.stream = stream; 441 return 0; 442 } 443 444 static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) 445 { 446 rewinddir(fs->dir.stream); 447 } 448 449 static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs) 450 { 451 return telldir(fs->dir.stream); 452 } 453 454 static struct dirent *local_readdir(FsContext *ctx, V9fsFidOpenState *fs) 455 { 456 struct dirent *entry; 457 458 again: 459 entry = readdir(fs->dir.stream); 460 if (!entry) { 461 return NULL; 462 } 463 464 if (ctx->export_flags & V9FS_SM_MAPPED) { 465 entry->d_type = DT_UNKNOWN; 466 } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 467 if (!strcmp(entry->d_name, VIRTFS_META_DIR)) { 468 /* skp the meta data directory */ 469 goto again; 470 } 471 entry->d_type = DT_UNKNOWN; 472 } 473 474 return entry; 475 } 476 477 static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) 478 { 479 seekdir(fs->dir.stream, off); 480 } 481 482 static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs, 483 const struct iovec *iov, 484 int iovcnt, off_t offset) 485 { 486 #ifdef CONFIG_PREADV 487 return preadv(fs->fd, iov, iovcnt, offset); 488 #else 489 int err = lseek(fs->fd, offset, SEEK_SET); 490 if (err == -1) { 491 return err; 492 } else { 493 return readv(fs->fd, iov, iovcnt); 494 } 495 #endif 496 } 497 498 static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs, 499 const struct iovec *iov, 500 int iovcnt, off_t offset) 501 { 502 ssize_t ret; 503 #ifdef CONFIG_PREADV 504 ret = pwritev(fs->fd, iov, iovcnt, offset); 505 #else 506 int err = lseek(fs->fd, offset, SEEK_SET); 507 if (err == -1) { 508 return err; 509 } else { 510 ret = writev(fs->fd, iov, iovcnt); 511 } 512 #endif 513 #ifdef CONFIG_SYNC_FILE_RANGE 514 if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) { 515 /* 516 * Initiate a writeback. This is not a data integrity sync. 517 * We want to ensure that we don't leave dirty pages in the cache 518 * after write when writeout=immediate is sepcified. 519 */ 520 sync_file_range(fs->fd, offset, ret, 521 SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE); 522 } 523 #endif 524 return ret; 525 } 526 527 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) 528 { 529 char *dirpath = g_path_get_dirname(fs_path->data); 530 char *name = g_path_get_basename(fs_path->data); 531 int ret = -1; 532 int dirfd; 533 534 dirfd = local_opendir_nofollow(fs_ctx, dirpath); 535 if (dirfd == -1) { 536 goto out; 537 } 538 539 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 540 ret = local_set_xattrat(dirfd, name, credp); 541 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 542 ret = local_set_mapped_file_attrat(dirfd, name, credp); 543 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 544 fs_ctx->export_flags & V9FS_SM_NONE) { 545 ret = fchmodat_nofollow(dirfd, name, credp->fc_mode); 546 } 547 close_preserve_errno(dirfd); 548 549 out: 550 g_free(dirpath); 551 g_free(name); 552 return ret; 553 } 554 555 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path, 556 const char *name, FsCred *credp) 557 { 558 int err = -1; 559 int dirfd; 560 561 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 562 if (dirfd == -1) { 563 return -1; 564 } 565 566 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 567 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 568 err = mknodat(dirfd, name, SM_LOCAL_MODE_BITS | S_IFREG, 0); 569 if (err == -1) { 570 goto out; 571 } 572 573 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 574 err = local_set_xattrat(dirfd, name, credp); 575 } else { 576 err = local_set_mapped_file_attrat(dirfd, name, credp); 577 } 578 if (err == -1) { 579 goto err_end; 580 } 581 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 582 fs_ctx->export_flags & V9FS_SM_NONE) { 583 err = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev); 584 if (err == -1) { 585 goto out; 586 } 587 err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); 588 if (err == -1) { 589 goto err_end; 590 } 591 } 592 goto out; 593 594 err_end: 595 unlinkat_preserve_errno(dirfd, name, 0); 596 out: 597 close_preserve_errno(dirfd); 598 return err; 599 } 600 601 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path, 602 const char *name, FsCred *credp) 603 { 604 int err = -1; 605 int dirfd; 606 607 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 608 if (dirfd == -1) { 609 return -1; 610 } 611 612 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 613 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 614 err = mkdirat(dirfd, name, SM_LOCAL_DIR_MODE_BITS); 615 if (err == -1) { 616 goto out; 617 } 618 credp->fc_mode = credp->fc_mode | S_IFDIR; 619 620 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 621 err = local_set_xattrat(dirfd, name, credp); 622 } else { 623 err = local_set_mapped_file_attrat(dirfd, name, credp); 624 } 625 if (err == -1) { 626 goto err_end; 627 } 628 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 629 fs_ctx->export_flags & V9FS_SM_NONE) { 630 err = mkdirat(dirfd, name, credp->fc_mode); 631 if (err == -1) { 632 goto out; 633 } 634 err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); 635 if (err == -1) { 636 goto err_end; 637 } 638 } 639 goto out; 640 641 err_end: 642 unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR); 643 out: 644 close_preserve_errno(dirfd); 645 return err; 646 } 647 648 static int local_fstat(FsContext *fs_ctx, int fid_type, 649 V9fsFidOpenState *fs, struct stat *stbuf) 650 { 651 int err, fd; 652 653 if (fid_type == P9_FID_DIR) { 654 fd = dirfd(fs->dir.stream); 655 } else { 656 fd = fs->fd; 657 } 658 659 err = fstat(fd, stbuf); 660 if (err) { 661 return err; 662 } 663 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 664 /* Actual credentials are part of extended attrs */ 665 uid_t tmp_uid; 666 gid_t tmp_gid; 667 mode_t tmp_mode; 668 dev_t tmp_dev; 669 670 if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) { 671 stbuf->st_uid = le32_to_cpu(tmp_uid); 672 } 673 if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) { 674 stbuf->st_gid = le32_to_cpu(tmp_gid); 675 } 676 if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) { 677 stbuf->st_mode = le32_to_cpu(tmp_mode); 678 } 679 if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) { 680 stbuf->st_rdev = le64_to_cpu(tmp_dev); 681 } 682 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 683 errno = EOPNOTSUPP; 684 return -1; 685 } 686 return err; 687 } 688 689 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, 690 int flags, FsCred *credp, V9fsFidOpenState *fs) 691 { 692 int fd = -1; 693 int err = -1; 694 int dirfd; 695 696 /* 697 * Mark all the open to not follow symlinks 698 */ 699 flags |= O_NOFOLLOW; 700 701 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 702 if (dirfd == -1) { 703 return -1; 704 } 705 706 /* Determine the security model */ 707 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 708 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 709 fd = openat_file(dirfd, name, flags, SM_LOCAL_MODE_BITS); 710 if (fd == -1) { 711 goto out; 712 } 713 credp->fc_mode = credp->fc_mode|S_IFREG; 714 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 715 /* Set cleint credentials in xattr */ 716 err = local_set_xattrat(dirfd, name, credp); 717 } else { 718 err = local_set_mapped_file_attrat(dirfd, name, credp); 719 } 720 if (err == -1) { 721 goto err_end; 722 } 723 } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || 724 (fs_ctx->export_flags & V9FS_SM_NONE)) { 725 fd = openat_file(dirfd, name, flags, credp->fc_mode); 726 if (fd == -1) { 727 goto out; 728 } 729 err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp); 730 if (err == -1) { 731 goto err_end; 732 } 733 } 734 err = fd; 735 fs->fd = fd; 736 goto out; 737 738 err_end: 739 unlinkat_preserve_errno(dirfd, name, 740 flags & O_DIRECTORY ? AT_REMOVEDIR : 0); 741 close_preserve_errno(fd); 742 out: 743 close_preserve_errno(dirfd); 744 return err; 745 } 746 747 748 static int local_symlink(FsContext *fs_ctx, const char *oldpath, 749 V9fsPath *dir_path, const char *name, FsCred *credp) 750 { 751 int err = -1; 752 int dirfd; 753 754 dirfd = local_opendir_nofollow(fs_ctx, dir_path->data); 755 if (dirfd == -1) { 756 return -1; 757 } 758 759 /* Determine the security model */ 760 if (fs_ctx->export_flags & V9FS_SM_MAPPED || 761 fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 762 int fd; 763 ssize_t oldpath_size, write_size; 764 765 fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR, 766 SM_LOCAL_MODE_BITS); 767 if (fd == -1) { 768 goto out; 769 } 770 /* Write the oldpath (target) to the file. */ 771 oldpath_size = strlen(oldpath); 772 do { 773 write_size = write(fd, (void *)oldpath, oldpath_size); 774 } while (write_size == -1 && errno == EINTR); 775 close_preserve_errno(fd); 776 777 if (write_size != oldpath_size) { 778 goto err_end; 779 } 780 /* Set cleint credentials in symlink's xattr */ 781 credp->fc_mode = credp->fc_mode | S_IFLNK; 782 783 if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 784 err = local_set_xattrat(dirfd, name, credp); 785 } else { 786 err = local_set_mapped_file_attrat(dirfd, name, credp); 787 } 788 if (err == -1) { 789 goto err_end; 790 } 791 } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH || 792 fs_ctx->export_flags & V9FS_SM_NONE) { 793 err = symlinkat(oldpath, dirfd, name); 794 if (err) { 795 goto out; 796 } 797 err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, 798 AT_SYMLINK_NOFOLLOW); 799 if (err == -1) { 800 /* 801 * If we fail to change ownership and if we are 802 * using security model none. Ignore the error 803 */ 804 if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) { 805 goto err_end; 806 } else { 807 err = 0; 808 } 809 } 810 } 811 goto out; 812 813 err_end: 814 unlinkat_preserve_errno(dirfd, name, 0); 815 out: 816 close_preserve_errno(dirfd); 817 return err; 818 } 819 820 static int local_link(FsContext *ctx, V9fsPath *oldpath, 821 V9fsPath *dirpath, const char *name) 822 { 823 char *odirpath = g_path_get_dirname(oldpath->data); 824 char *oname = g_path_get_basename(oldpath->data); 825 int ret = -1; 826 int odirfd, ndirfd; 827 828 odirfd = local_opendir_nofollow(ctx, odirpath); 829 if (odirfd == -1) { 830 goto out; 831 } 832 833 ndirfd = local_opendir_nofollow(ctx, dirpath->data); 834 if (ndirfd == -1) { 835 close_preserve_errno(odirfd); 836 goto out; 837 } 838 839 ret = linkat(odirfd, oname, ndirfd, name, 0); 840 if (ret < 0) { 841 goto out_close; 842 } 843 844 /* now link the virtfs_metadata files */ 845 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 846 int omap_dirfd, nmap_dirfd; 847 848 ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700); 849 if (ret < 0 && errno != EEXIST) { 850 goto err_undo_link; 851 } 852 853 omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR); 854 if (omap_dirfd == -1) { 855 goto err; 856 } 857 858 nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR); 859 if (nmap_dirfd == -1) { 860 close_preserve_errno(omap_dirfd); 861 goto err; 862 } 863 864 ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0); 865 close_preserve_errno(nmap_dirfd); 866 close_preserve_errno(omap_dirfd); 867 if (ret < 0 && errno != ENOENT) { 868 goto err_undo_link; 869 } 870 871 ret = 0; 872 } 873 goto out_close; 874 875 err: 876 ret = -1; 877 err_undo_link: 878 unlinkat_preserve_errno(ndirfd, name, 0); 879 out_close: 880 close_preserve_errno(ndirfd); 881 close_preserve_errno(odirfd); 882 out: 883 g_free(oname); 884 g_free(odirpath); 885 return ret; 886 } 887 888 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size) 889 { 890 int fd, ret; 891 892 fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0); 893 if (fd == -1) { 894 return -1; 895 } 896 ret = ftruncate(fd, size); 897 close_preserve_errno(fd); 898 return ret; 899 } 900 901 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp) 902 { 903 char *dirpath = g_path_get_dirname(fs_path->data); 904 char *name = g_path_get_basename(fs_path->data); 905 int ret = -1; 906 int dirfd; 907 908 dirfd = local_opendir_nofollow(fs_ctx, dirpath); 909 if (dirfd == -1) { 910 goto out; 911 } 912 913 if ((credp->fc_uid == -1 && credp->fc_gid == -1) || 914 (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || 915 (fs_ctx->export_flags & V9FS_SM_NONE)) { 916 ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid, 917 AT_SYMLINK_NOFOLLOW); 918 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) { 919 ret = local_set_xattrat(dirfd, name, credp); 920 } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) { 921 ret = local_set_mapped_file_attrat(dirfd, name, credp); 922 } 923 924 close_preserve_errno(dirfd); 925 out: 926 g_free(name); 927 g_free(dirpath); 928 return ret; 929 } 930 931 static int local_utimensat(FsContext *s, V9fsPath *fs_path, 932 const struct timespec *buf) 933 { 934 char *dirpath = g_path_get_dirname(fs_path->data); 935 char *name = g_path_get_basename(fs_path->data); 936 int dirfd, ret = -1; 937 938 dirfd = local_opendir_nofollow(s, dirpath); 939 if (dirfd == -1) { 940 goto out; 941 } 942 943 ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW); 944 close_preserve_errno(dirfd); 945 out: 946 g_free(dirpath); 947 g_free(name); 948 return ret; 949 } 950 951 static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name, 952 int flags) 953 { 954 int ret = -1; 955 956 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 957 int map_dirfd; 958 959 if (flags == AT_REMOVEDIR) { 960 int fd; 961 962 fd = openat(dirfd, name, O_RDONLY | O_DIRECTORY | O_PATH); 963 if (fd == -1) { 964 goto err_out; 965 } 966 /* 967 * If directory remove .virtfs_metadata contained in the 968 * directory 969 */ 970 ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR); 971 close_preserve_errno(fd); 972 if (ret < 0 && errno != ENOENT) { 973 /* 974 * We didn't had the .virtfs_metadata file. May be file created 975 * in non-mapped mode ?. Ignore ENOENT. 976 */ 977 goto err_out; 978 } 979 } 980 /* 981 * Now remove the name from parent directory 982 * .virtfs_metadata directory. 983 */ 984 map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR); 985 ret = unlinkat(map_dirfd, name, 0); 986 close_preserve_errno(map_dirfd); 987 if (ret < 0 && errno != ENOENT) { 988 /* 989 * We didn't had the .virtfs_metadata file. May be file created 990 * in non-mapped mode ?. Ignore ENOENT. 991 */ 992 goto err_out; 993 } 994 } 995 996 ret = unlinkat(dirfd, name, flags); 997 err_out: 998 return ret; 999 } 1000 1001 static int local_remove(FsContext *ctx, const char *path) 1002 { 1003 struct stat stbuf; 1004 char *dirpath = g_path_get_dirname(path); 1005 char *name = g_path_get_basename(path); 1006 int flags = 0; 1007 int dirfd; 1008 int err = -1; 1009 1010 dirfd = local_opendir_nofollow(ctx, dirpath); 1011 if (dirfd) { 1012 goto out; 1013 } 1014 1015 if (fstatat(dirfd, path, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) { 1016 goto err_out; 1017 } 1018 1019 if (S_ISDIR(stbuf.st_mode)) { 1020 flags |= AT_REMOVEDIR; 1021 } 1022 1023 err = local_unlinkat_common(ctx, dirfd, name, flags); 1024 err_out: 1025 close_preserve_errno(dirfd); 1026 out: 1027 g_free(name); 1028 g_free(dirpath); 1029 return err; 1030 } 1031 1032 static int local_fsync(FsContext *ctx, int fid_type, 1033 V9fsFidOpenState *fs, int datasync) 1034 { 1035 int fd; 1036 1037 if (fid_type == P9_FID_DIR) { 1038 fd = dirfd(fs->dir.stream); 1039 } else { 1040 fd = fs->fd; 1041 } 1042 1043 if (datasync) { 1044 return qemu_fdatasync(fd); 1045 } else { 1046 return fsync(fd); 1047 } 1048 } 1049 1050 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) 1051 { 1052 int fd, ret; 1053 1054 fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0); 1055 ret = fstatfs(fd, stbuf); 1056 close_preserve_errno(fd); 1057 return ret; 1058 } 1059 1060 static ssize_t local_lgetxattr(FsContext *ctx, V9fsPath *fs_path, 1061 const char *name, void *value, size_t size) 1062 { 1063 char *path = fs_path->data; 1064 1065 return v9fs_get_xattr(ctx, path, name, value, size); 1066 } 1067 1068 static ssize_t local_llistxattr(FsContext *ctx, V9fsPath *fs_path, 1069 void *value, size_t size) 1070 { 1071 char *path = fs_path->data; 1072 1073 return v9fs_list_xattr(ctx, path, value, size); 1074 } 1075 1076 static int local_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name, 1077 void *value, size_t size, int flags) 1078 { 1079 char *path = fs_path->data; 1080 1081 return v9fs_set_xattr(ctx, path, name, value, size, flags); 1082 } 1083 1084 static int local_lremovexattr(FsContext *ctx, V9fsPath *fs_path, 1085 const char *name) 1086 { 1087 char *path = fs_path->data; 1088 1089 return v9fs_remove_xattr(ctx, path, name); 1090 } 1091 1092 static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path, 1093 const char *name, V9fsPath *target) 1094 { 1095 if (dir_path) { 1096 v9fs_path_sprintf(target, "%s/%s", dir_path->data, name); 1097 } else { 1098 v9fs_path_sprintf(target, "%s", name); 1099 } 1100 return 0; 1101 } 1102 1103 static int local_renameat(FsContext *ctx, V9fsPath *olddir, 1104 const char *old_name, V9fsPath *newdir, 1105 const char *new_name) 1106 { 1107 int ret; 1108 int odirfd, ndirfd; 1109 1110 odirfd = local_opendir_nofollow(ctx, olddir->data); 1111 if (odirfd == -1) { 1112 return -1; 1113 } 1114 1115 ndirfd = local_opendir_nofollow(ctx, newdir->data); 1116 if (ndirfd == -1) { 1117 close_preserve_errno(odirfd); 1118 return -1; 1119 } 1120 1121 ret = renameat(odirfd, old_name, ndirfd, new_name); 1122 if (ret < 0) { 1123 goto out; 1124 } 1125 1126 if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 1127 int omap_dirfd, nmap_dirfd; 1128 1129 ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700); 1130 if (ret < 0 && errno != EEXIST) { 1131 goto err_undo_rename; 1132 } 1133 1134 omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR); 1135 if (omap_dirfd == -1) { 1136 goto err; 1137 } 1138 1139 nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR); 1140 if (nmap_dirfd == -1) { 1141 close_preserve_errno(omap_dirfd); 1142 goto err; 1143 } 1144 1145 /* rename the .virtfs_metadata files */ 1146 ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name); 1147 close_preserve_errno(nmap_dirfd); 1148 close_preserve_errno(omap_dirfd); 1149 if (ret < 0 && errno != ENOENT) { 1150 goto err_undo_rename; 1151 } 1152 1153 ret = 0; 1154 } 1155 goto out; 1156 1157 err: 1158 ret = -1; 1159 err_undo_rename: 1160 renameat_preserve_errno(ndirfd, new_name, odirfd, old_name); 1161 out: 1162 close_preserve_errno(ndirfd); 1163 close_preserve_errno(odirfd); 1164 return ret; 1165 } 1166 1167 static void v9fs_path_init_dirname(V9fsPath *path, const char *str) 1168 { 1169 path->data = g_path_get_dirname(str); 1170 path->size = strlen(path->data) + 1; 1171 } 1172 1173 static int local_rename(FsContext *ctx, const char *oldpath, 1174 const char *newpath) 1175 { 1176 int err; 1177 char *oname = g_path_get_basename(oldpath); 1178 char *nname = g_path_get_basename(newpath); 1179 V9fsPath olddir, newdir; 1180 1181 v9fs_path_init_dirname(&olddir, oldpath); 1182 v9fs_path_init_dirname(&newdir, newpath); 1183 1184 err = local_renameat(ctx, &olddir, oname, &newdir, nname); 1185 1186 v9fs_path_free(&newdir); 1187 v9fs_path_free(&olddir); 1188 g_free(nname); 1189 g_free(oname); 1190 1191 return err; 1192 } 1193 1194 static int local_unlinkat(FsContext *ctx, V9fsPath *dir, 1195 const char *name, int flags) 1196 { 1197 int ret; 1198 int dirfd; 1199 1200 dirfd = local_opendir_nofollow(ctx, dir->data); 1201 if (dirfd == -1) { 1202 return -1; 1203 } 1204 1205 ret = local_unlinkat_common(ctx, dirfd, name, flags); 1206 close_preserve_errno(dirfd); 1207 return ret; 1208 } 1209 1210 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path, 1211 mode_t st_mode, uint64_t *st_gen) 1212 { 1213 #ifdef FS_IOC_GETVERSION 1214 int err; 1215 V9fsFidOpenState fid_open; 1216 1217 /* 1218 * Do not try to open special files like device nodes, fifos etc 1219 * We can get fd for regular files and directories only 1220 */ 1221 if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) { 1222 errno = ENOTTY; 1223 return -1; 1224 } 1225 err = local_open(ctx, path, O_RDONLY, &fid_open); 1226 if (err < 0) { 1227 return err; 1228 } 1229 err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen); 1230 local_close(ctx, &fid_open); 1231 return err; 1232 #else 1233 errno = ENOTTY; 1234 return -1; 1235 #endif 1236 } 1237 1238 static int local_init(FsContext *ctx) 1239 { 1240 struct statfs stbuf; 1241 LocalData *data = g_malloc(sizeof(*data)); 1242 1243 data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY); 1244 if (data->mountfd == -1) { 1245 goto err; 1246 } 1247 1248 #ifdef FS_IOC_GETVERSION 1249 /* 1250 * use ioc_getversion only if the ioctl is definied 1251 */ 1252 if (fstatfs(data->mountfd, &stbuf) < 0) { 1253 close_preserve_errno(data->mountfd); 1254 goto err; 1255 } 1256 switch (stbuf.f_type) { 1257 case EXT2_SUPER_MAGIC: 1258 case BTRFS_SUPER_MAGIC: 1259 case REISERFS_SUPER_MAGIC: 1260 case XFS_SUPER_MAGIC: 1261 ctx->exops.get_st_gen = local_ioc_getversion; 1262 break; 1263 } 1264 #endif 1265 1266 if (ctx->export_flags & V9FS_SM_PASSTHROUGH) { 1267 ctx->xops = passthrough_xattr_ops; 1268 } else if (ctx->export_flags & V9FS_SM_MAPPED) { 1269 ctx->xops = mapped_xattr_ops; 1270 } else if (ctx->export_flags & V9FS_SM_NONE) { 1271 ctx->xops = none_xattr_ops; 1272 } else if (ctx->export_flags & V9FS_SM_MAPPED_FILE) { 1273 /* 1274 * xattr operation for mapped-file and passthrough 1275 * remain same. 1276 */ 1277 ctx->xops = passthrough_xattr_ops; 1278 } 1279 ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT; 1280 1281 ctx->private = data; 1282 return 0; 1283 1284 err: 1285 g_free(data); 1286 return -1; 1287 } 1288 1289 static void local_cleanup(FsContext *ctx) 1290 { 1291 LocalData *data = ctx->private; 1292 1293 close(data->mountfd); 1294 g_free(data); 1295 } 1296 1297 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse) 1298 { 1299 const char *sec_model = qemu_opt_get(opts, "security_model"); 1300 const char *path = qemu_opt_get(opts, "path"); 1301 Error *err = NULL; 1302 1303 if (!sec_model) { 1304 error_report("Security model not specified, local fs needs security model"); 1305 error_printf("valid options are:" 1306 "\tsecurity_model=[passthrough|mapped-xattr|mapped-file|none]\n"); 1307 return -1; 1308 } 1309 1310 if (!strcmp(sec_model, "passthrough")) { 1311 fse->export_flags |= V9FS_SM_PASSTHROUGH; 1312 } else if (!strcmp(sec_model, "mapped") || 1313 !strcmp(sec_model, "mapped-xattr")) { 1314 fse->export_flags |= V9FS_SM_MAPPED; 1315 } else if (!strcmp(sec_model, "none")) { 1316 fse->export_flags |= V9FS_SM_NONE; 1317 } else if (!strcmp(sec_model, "mapped-file")) { 1318 fse->export_flags |= V9FS_SM_MAPPED_FILE; 1319 } else { 1320 error_report("Invalid security model %s specified", sec_model); 1321 error_printf("valid options are:" 1322 "\t[passthrough|mapped-xattr|mapped-file|none]\n"); 1323 return -1; 1324 } 1325 1326 if (!path) { 1327 error_report("fsdev: No path specified"); 1328 return -1; 1329 } 1330 1331 fsdev_throttle_parse_opts(opts, &fse->fst, &err); 1332 if (err) { 1333 error_reportf_err(err, "Throttle configuration is not valid: "); 1334 return -1; 1335 } 1336 1337 fse->path = g_strdup(path); 1338 1339 return 0; 1340 } 1341 1342 FileOperations local_ops = { 1343 .parse_opts = local_parse_opts, 1344 .init = local_init, 1345 .cleanup = local_cleanup, 1346 .lstat = local_lstat, 1347 .readlink = local_readlink, 1348 .close = local_close, 1349 .closedir = local_closedir, 1350 .open = local_open, 1351 .opendir = local_opendir, 1352 .rewinddir = local_rewinddir, 1353 .telldir = local_telldir, 1354 .readdir = local_readdir, 1355 .seekdir = local_seekdir, 1356 .preadv = local_preadv, 1357 .pwritev = local_pwritev, 1358 .chmod = local_chmod, 1359 .mknod = local_mknod, 1360 .mkdir = local_mkdir, 1361 .fstat = local_fstat, 1362 .open2 = local_open2, 1363 .symlink = local_symlink, 1364 .link = local_link, 1365 .truncate = local_truncate, 1366 .rename = local_rename, 1367 .chown = local_chown, 1368 .utimensat = local_utimensat, 1369 .remove = local_remove, 1370 .fsync = local_fsync, 1371 .statfs = local_statfs, 1372 .lgetxattr = local_lgetxattr, 1373 .llistxattr = local_llistxattr, 1374 .lsetxattr = local_lsetxattr, 1375 .lremovexattr = local_lremovexattr, 1376 .name_to_path = local_name_to_path, 1377 .renameat = local_renameat, 1378 .unlinkat = local_unlinkat, 1379 }; 1380