Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 | /* * linux/fs/open.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include <linux/string.h> #include <linux/mm.h> #include <linux/utime.h> #include <linux/file.h> #include <linux/smp_lock.h> #include <linux/quotaops.h> #include <linux/dnotify.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/tty.h> #include <linux/namei.h> #include <linux/backing-dev.h> #include <linux/security.h> #include <linux/mount.h> #include <linux/vfs.h> #include <asm/uaccess.h> #include <linux/fs.h> #include <linux/pagemap.h> #include <linux/syscalls.h> #include <asm/unistd.h> int vfs_statfs(struct super_block *sb, struct kstatfs *buf) { int retval = -ENODEV; if (sb) { retval = -ENOSYS; if (sb->s_op->statfs) { memset(buf, 0, sizeof(*buf)); retval = security_sb_statfs(sb); if (retval) return retval; retval = sb->s_op->statfs(sb, buf); if (retval == 0 && buf->f_frsize == 0) buf->f_frsize = buf->f_bsize; } } return retval; } EXPORT_SYMBOL(vfs_statfs); static int vfs_statfs_native(struct super_block *sb, struct statfs *buf) { struct kstatfs st; int retval; retval = vfs_statfs(sb, &st); if (retval) return retval; if (sizeof(*buf) == sizeof(st)) memcpy(buf, &st, sizeof(st)); else { if (sizeof buf->f_blocks == 4) { if ((st.f_blocks | st.f_bfree | st.f_bavail) & 0xffffffff00000000ULL) return -EOVERFLOW; /* * f_files and f_ffree may be -1; it's okay to stuff * that into 32 bits */ if (st.f_files != -1 && (st.f_files & 0xffffffff00000000ULL)) return -EOVERFLOW; if (st.f_ffree != -1 && (st.f_ffree & 0xffffffff00000000ULL)) return -EOVERFLOW; } buf->f_type = st.f_type; buf->f_bsize = st.f_bsize; buf->f_blocks = st.f_blocks; buf->f_bfree = st.f_bfree; buf->f_bavail = st.f_bavail; buf->f_files = st.f_files; buf->f_ffree = st.f_ffree; buf->f_fsid = st.f_fsid; buf->f_namelen = st.f_namelen; buf->f_frsize = st.f_frsize; memset(buf->f_spare, 0, sizeof(buf->f_spare)); } return 0; } static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf) { struct kstatfs st; int retval; retval = vfs_statfs(sb, &st); if (retval) return retval; if (sizeof(*buf) == sizeof(st)) memcpy(buf, &st, sizeof(st)); else { buf->f_type = st.f_type; buf->f_bsize = st.f_bsize; buf->f_blocks = st.f_blocks; buf->f_bfree = st.f_bfree; buf->f_bavail = st.f_bavail; buf->f_files = st.f_files; buf->f_ffree = st.f_ffree; buf->f_fsid = st.f_fsid; buf->f_namelen = st.f_namelen; buf->f_frsize = st.f_frsize; memset(buf->f_spare, 0, sizeof(buf->f_spare)); } return 0; } asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf) { struct nameidata nd; int error; error = user_path_walk(path, &nd); if (!error) { struct statfs tmp; error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp); if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) error = -EFAULT; path_release(&nd); } return error; } asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf) { struct nameidata nd; long error; if (sz != sizeof(*buf)) return -EINVAL; error = user_path_walk(path, &nd); if (!error) { struct statfs64 tmp; error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp); if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) error = -EFAULT; path_release(&nd); } return error; } asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf) { struct file * file; struct statfs tmp; int error; error = -EBADF; file = fget(fd); if (!file) goto out; error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp); if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) error = -EFAULT; fput(file); out: return error; } asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf) { struct file * file; struct statfs64 tmp; int error; if (sz != sizeof(*buf)) return -EINVAL; error = -EBADF; file = fget(fd); if (!file) goto out; error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp); if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) error = -EFAULT; fput(file); out: return error; } int do_truncate(struct dentry *dentry, loff_t length) { int err; struct iattr newattrs; /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ if (length < 0) return -EINVAL; newattrs.ia_size = length; newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; down(&dentry->d_inode->i_sem); err = notify_change(dentry, &newattrs); up(&dentry->d_inode->i_sem); return err; } static inline long do_sys_truncate(const char __user * path, loff_t length) { struct nameidata nd; struct inode * inode; int error; error = -EINVAL; if (length < 0) /* sorry, but loff_t says... */ goto out; error = user_path_walk(path, &nd); if (error) goto out; inode = nd.dentry->d_inode; /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ error = -EISDIR; if (S_ISDIR(inode->i_mode)) goto dput_and_out; error = -EINVAL; if (!S_ISREG(inode->i_mode)) goto dput_and_out; error = permission(inode,MAY_WRITE,&nd); if (error) goto dput_and_out; error = -EROFS; if (IS_RDONLY(inode)) goto dput_and_out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto dput_and_out; /* * Make sure that there are no leases. */ error = break_lease(inode, FMODE_WRITE); if (error) goto dput_and_out; error = get_write_access(inode); if (error) goto dput_and_out; error = locks_verify_truncate(inode, NULL, length); if (!error) { DQUOT_INIT(inode); error = do_truncate(nd.dentry, length); } put_write_access(inode); dput_and_out: path_release(&nd); out: return error; } asmlinkage long sys_truncate(const char __user * path, unsigned long length) { /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */ return do_sys_truncate(path, (long)length); } static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small) { struct inode * inode; struct dentry *dentry; struct file * file; int error; error = -EINVAL; if (length < 0) goto out; error = -EBADF; file = fget(fd); if (!file) goto out; /* explicitly opened as large or we are on 64-bit box */ if (file->f_flags & O_LARGEFILE) small = 0; dentry = file->f_dentry; inode = dentry->d_inode; error = -EINVAL; if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) goto out_putf; error = -EINVAL; /* Cannot ftruncate over 2^31 bytes without large file support */ if (small && length > MAX_NON_LFS) goto out_putf; error = -EPERM; if (IS_APPEND(inode)) goto out_putf; error = locks_verify_truncate(inode, file, length); if (!error) error = do_truncate(dentry, length); out_putf: fput(file); out: return error; } asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) { return do_sys_ftruncate(fd, length, 1); } /* LFS versions of truncate are only needed on 32 bit machines */ #if BITS_PER_LONG == 32 asmlinkage long sys_truncate64(const char __user * path, loff_t length) { return do_sys_truncate(path, length); } asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) { return do_sys_ftruncate(fd, length, 0); } #endif #ifdef __ARCH_WANT_SYS_UTIME /* * sys_utime() can be implemented in user-level using sys_utimes(). * Is this for backwards compatibility? If so, why not move it * into the appropriate arch directory (for those architectures that * need it). */ /* If times==NULL, set access and modification to current time, * must be owner or have write permission. * Else, update from *times, must be owner or super user. */ asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times) { int error; struct nameidata nd; struct inode * inode; struct iattr newattrs; error = user_path_walk(filename, &nd); if (error) goto out; inode = nd.dentry->d_inode; error = -EROFS; if (IS_RDONLY(inode)) goto dput_and_out; /* Don't worry, the checks are done in inode_change_ok() */ newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; if (times) { error = -EPERM; if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) goto dput_and_out; error = get_user(newattrs.ia_atime.tv_sec, ×->actime); newattrs.ia_atime.tv_nsec = 0; if (!error) error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime); newattrs.ia_mtime.tv_nsec = 0; if (error) goto dput_and_out; newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; } else { error = -EACCES; if (IS_IMMUTABLE(inode)) goto dput_and_out; if (current->fsuid != inode->i_uid && (error = permission(inode,MAY_WRITE,&nd)) != 0) goto dput_and_out; } down(&inode->i_sem); error = notify_change(nd.dentry, &newattrs); up(&inode->i_sem); dput_and_out: path_release(&nd); out: return error; } #endif /* If times==NULL, set access and modification to current time, * must be owner or have write permission. * Else, update from *times, must be owner or super user. */ long do_utimes(char __user * filename, struct timeval * times) { int error; struct nameidata nd; struct inode * inode; struct iattr newattrs; error = user_path_walk(filename, &nd); if (error) goto out; inode = nd.dentry->d_inode; error = -EROFS; if (IS_RDONLY(inode)) goto dput_and_out; /* Don't worry, the checks are done in inode_change_ok() */ newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; if (times) { error = -EPERM; if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) goto dput_and_out; newattrs.ia_atime.tv_sec = times[0].tv_sec; newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000; newattrs.ia_mtime.tv_sec = times[1].tv_sec; newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000; newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; } else { error = -EACCES; if (IS_IMMUTABLE(inode)) goto dput_and_out; if (current->fsuid != inode->i_uid && (error = permission(inode,MAY_WRITE,&nd)) != 0) goto dput_and_out; } down(&inode->i_sem); error = notify_change(nd.dentry, &newattrs); up(&inode->i_sem); dput_and_out: path_release(&nd); out: return error; } asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes) { struct timeval times[2]; if (utimes && copy_from_user(×, utimes, sizeof(times))) return -EFAULT; return do_utimes(filename, utimes ? times : NULL); } /* * access() needs to use the real uid/gid, not the effective uid/gid. * We do this by temporarily clearing all FS-related capabilities and * switching the fsuid/fsgid around to the real ones. */ asmlinkage long sys_access(const char __user * filename, int mode) { struct nameidata nd; int old_fsuid, old_fsgid; kernel_cap_t old_cap; int res; if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ return -EINVAL; old_fsuid = current->fsuid; old_fsgid = current->fsgid; old_cap = current->cap_effective; current->fsuid = current->uid; current->fsgid = current->gid; /* * Clear the capabilities if we switch to a non-root user * * FIXME: There is a race here against sys_capset. The * capabilities can change yet we will restore the old * value below. We should hold task_capabilities_lock, * but we cannot because user_path_walk can sleep. */ if (current->uid) cap_clear(current->cap_effective); else current->cap_effective = current->cap_permitted; res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd); if (!res) { res = permission(nd.dentry->d_inode, mode, &nd); /* SuS v2 requires we report a read only fs too */ if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode) && !special_file(nd.dentry->d_inode->i_mode)) res = -EROFS; path_release(&nd); } current->fsuid = old_fsuid; current->fsgid = old_fsgid; current->cap_effective = old_cap; return res; } asmlinkage long sys_chdir(const char __user * filename) { struct nameidata nd; int error; error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); if (error) goto out; error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); if (error) goto dput_and_out; set_fs_pwd(current->fs, nd.mnt, nd.dentry); dput_and_out: path_release(&nd); out: return error; } asmlinkage long sys_fchdir(unsigned int fd) { struct file *file; struct dentry *dentry; struct inode *inode; struct vfsmount *mnt; int error; error = -EBADF; file = fget(fd); if (!file) goto out; dentry = file->f_dentry; mnt = file->f_vfsmnt; inode = dentry->d_inode; error = -ENOTDIR; if (!S_ISDIR(inode->i_mode)) goto out_putf; error = permission(inode, MAY_EXEC, NULL); if (!error) set_fs_pwd(current->fs, mnt, dentry); out_putf: fput(file); out: return error; } asmlinkage long sys_chroot(const char __user * filename) { struct nameidata nd; int error; error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd); if (error) goto out; error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); if (error) goto dput_and_out; error = -EPERM; if (!capable(CAP_SYS_CHROOT)) goto dput_and_out; set_fs_root(current->fs, nd.mnt, nd.dentry); set_fs_altroot(); error = 0; dput_and_out: path_release(&nd); out: return error; } asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) { struct inode * inode; struct dentry * dentry; struct file * file; int err = -EBADF; struct iattr newattrs; file = fget(fd); if (!file) goto out; dentry = file->f_dentry; inode = dentry->d_inode; err = -EROFS; if (IS_RDONLY(inode)) goto out_putf; err = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto out_putf; down(&inode->i_sem); if (mode == (mode_t) -1) mode = inode->i_mode; newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; err = notify_change(dentry, &newattrs); up(&inode->i_sem); out_putf: fput(file); out: return err; } asmlinkage long sys_chmod(const char __user * filename, mode_t mode) { struct nameidata nd; struct inode * inode; int error; struct iattr newattrs; error = user_path_walk(filename, &nd); if (error) goto out; inode = nd.dentry->d_inode; error = -EROFS; if (IS_RDONLY(inode)) goto dput_and_out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto dput_and_out; down(&inode->i_sem); if (mode == (mode_t) -1) mode = inode->i_mode; newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; error = notify_change(nd.dentry, &newattrs); up(&inode->i_sem); dput_and_out: path_release(&nd); out: return error; } static int chown_common(struct dentry * dentry, uid_t user, gid_t group) { struct inode * inode; int error; struct iattr newattrs; error = -ENOENT; if (!(inode = dentry->d_inode)) { printk(KERN_ERR "chown_common: NULL inode\n"); goto out; } error = -EROFS; if (IS_RDONLY(inode)) goto out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto out; newattrs.ia_valid = ATTR_CTIME; if (user != (uid_t) -1) { newattrs.ia_valid |= ATTR_UID; newattrs.ia_uid = user; } if (group != (gid_t) -1) { newattrs.ia_valid |= ATTR_GID; newattrs.ia_gid = group; } if (!S_ISDIR(inode->i_mode)) newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID; down(&inode->i_sem); error = notify_change(dentry, &newattrs); up(&inode->i_sem); out: return error; } asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) { struct nameidata nd; int error; error = user_path_walk(filename, &nd); if (!error) { error = chown_common(nd.dentry, user, group); path_release(&nd); } return error; } asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group) { struct nameidata nd; int error; error = user_path_walk_link(filename, &nd); if (!error) { error = chown_common(nd.dentry, user, group); path_release(&nd); } return error; } asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) { struct file * file; int error = -EBADF; file = fget(fd); if (file) { error = chown_common(file->f_dentry, user, group); fput(file); } return error; } /* * Note that while the flag value (low two bits) for sys_open means: * 00 - read-only * 01 - write-only * 10 - read-write * 11 - special * it is changed into * 00 - no permissions needed * 01 - read-permission * 10 - write-permission * 11 - read-write * for the internal routines (ie open_namei()/follow_link() etc). 00 is * used by symlinks. */ struct file *filp_open(const char * filename, int flags, int mode) { int namei_flags, error; struct nameidata nd; namei_flags = flags; if ((namei_flags+1) & O_ACCMODE) namei_flags++; if (namei_flags & O_TRUNC) namei_flags |= 2; error = open_namei(filename, namei_flags, mode, &nd); if (!error) return dentry_open(nd.dentry, nd.mnt, flags); return ERR_PTR(error); } EXPORT_SYMBOL(filp_open); struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) { struct file * f; struct inode *inode; int error; error = -ENFILE; f = get_empty_filp(); if (!f) goto cleanup_dentry; f->f_flags = flags; f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; inode = dentry->d_inode; if (f->f_mode & FMODE_WRITE) { error = get_write_access(inode); if (error) goto cleanup_file; } f->f_mapping = inode->i_mapping; f->f_dentry = dentry; f->f_vfsmnt = mnt; f->f_pos = 0; f->f_op = fops_get(inode->i_fop); file_move(f, &inode->i_sb->s_files); if (f->f_op && f->f_op->open) { error = f->f_op->open(inode,f); if (error) goto cleanup_all; } f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); /* NB: we're sure to have correct a_ops only after f_op->open */ if (f->f_flags & O_DIRECT) { if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) { fput(f); f = ERR_PTR(-EINVAL); } } return f; cleanup_all: fops_put(f->f_op); if (f->f_mode & FMODE_WRITE) put_write_access(inode); file_kill(f); f->f_dentry = NULL; f->f_vfsmnt = NULL; cleanup_file: put_filp(f); cleanup_dentry: dput(dentry); mntput(mnt); return ERR_PTR(error); } EXPORT_SYMBOL(dentry_open); /* * Find an empty file descriptor entry, and mark it busy. */ int get_unused_fd(void) { struct files_struct * files = current->files; int fd, error; error = -EMFILE; spin_lock(&files->file_lock); repeat: fd = find_next_zero_bit(files->open_fds->fds_bits, files->max_fdset, files->next_fd); /* * N.B. For clone tasks sharing a files structure, this test * will limit the total number of files that can be opened. */ if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) goto out; /* Do we need to expand the fd array or fd set? */ error = expand_files(files, fd); if (error < 0) goto out; if (error) { /* * If we needed to expand the fs array we * might have blocked - try again. */ error = -EMFILE; goto repeat; } FD_SET(fd, files->open_fds); FD_CLR(fd, files->close_on_exec); files->next_fd = fd + 1; #if 1 /* Sanity check */ if (files->fd[fd] != NULL) { printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd); files->fd[fd] = NULL; } #endif error = fd; out: spin_unlock(&files->file_lock); return error; } EXPORT_SYMBOL(get_unused_fd); static inline void __put_unused_fd(struct files_struct *files, unsigned int fd) { __FD_CLR(fd, files->open_fds); if (fd < files->next_fd) files->next_fd = fd; } void fastcall put_unused_fd(unsigned int fd) { struct files_struct *files = current->files; spin_lock(&files->file_lock); __put_unused_fd(files, fd); spin_unlock(&files->file_lock); } EXPORT_SYMBOL(put_unused_fd); /* * Install a file pointer in the fd array. * * The VFS is full of places where we drop the files lock between * setting the open_fds bitmap and installing the file in the file * array. At any such point, we are vulnerable to a dup2() race * installing a file in the array before us. We need to detect this and * fput() the struct file we are about to overwrite in this case. * * It should never happen - if we allow dup2() do it, _really_ bad things * will follow. */ void fastcall fd_install(unsigned int fd, struct file * file) { struct files_struct *files = current->files; spin_lock(&files->file_lock); if (unlikely(files->fd[fd] != NULL)) BUG(); files->fd[fd] = file; spin_unlock(&files->file_lock); } EXPORT_SYMBOL(fd_install); asmlinkage long sys_open(const char __user * filename, int flags, int mode) { char * tmp; int fd, error; #if BITS_PER_LONG != 32 flags |= O_LARGEFILE; #endif tmp = getname(filename); fd = PTR_ERR(tmp); if (!IS_ERR(tmp)) { fd = get_unused_fd(); if (fd >= 0) { struct file *f = filp_open(tmp, flags, mode); error = PTR_ERR(f); if (IS_ERR(f)) goto out_error; fd_install(fd, f); } out: putname(tmp); } return fd; out_error: put_unused_fd(fd); fd = error; goto out; } EXPORT_SYMBOL_GPL(sys_open); #ifndef __alpha__ /* * For backward compatibility? Maybe this should be moved * into arch/i386 instead? */ asmlinkage long sys_creat(const char __user * pathname, int mode) { return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); } #endif /* * "id" is the POSIX thread ID. We use the * files pointer for this.. */ int filp_close(struct file *filp, fl_owner_t id) { int retval; /* Report and clear outstanding errors */ retval = filp->f_error; if (retval) filp->f_error = 0; if (!file_count(filp)) { printk(KERN_ERR "VFS: Close: file count is 0\n"); return retval; } if (filp->f_op && filp->f_op->flush) { int err = filp->f_op->flush(filp); if (!retval) retval = err; } dnotify_flush(filp, id); locks_remove_posix(filp, id); fput(filp); return retval; } EXPORT_SYMBOL(filp_close); /* * Careful here! We test whether the file pointer is NULL before * releasing the fd. This ensures that one clone task can't release * an fd while another clone is opening it. */ asmlinkage long sys_close(unsigned int fd) { struct file * filp; struct files_struct *files = current->files; spin_lock(&files->file_lock); if (fd >= files->max_fds) goto out_unlock; filp = files->fd[fd]; if (!filp) goto out_unlock; files->fd[fd] = NULL; FD_CLR(fd, files->close_on_exec); __put_unused_fd(files, fd); spin_unlock(&files->file_lock); return filp_close(filp, files); out_unlock: spin_unlock(&files->file_lock); return -EBADF; } EXPORT_SYMBOL(sys_close); /* * This routine simulates a hangup on the tty, to arrange that users * are given clean terminals at login time. */ asmlinkage long sys_vhangup(void) { if (capable(CAP_SYS_TTY_CONFIG)) { tty_vhangup(current->signal->tty); return 0; } return -EPERM; } /* * Called when an inode is about to be open. * We use this to disallow opening large files on 32bit systems if * the caller didn't specify O_LARGEFILE. On 64bit systems we force * on this flag in sys_open. */ int generic_file_open(struct inode * inode, struct file * filp) { if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) return -EFBIG; return 0; } EXPORT_SYMBOL(generic_file_open); /* * This is used by subsystems that don't want seekable * file descriptors */ int nonseekable_open(struct inode *inode, struct file *filp) { filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); return 0; } EXPORT_SYMBOL(nonseekable_open); |