1/* 2 * linux/fs/open.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7#include <linux/string.h> 8#include <linux/mm.h> 9#include <linux/file.h> 10#include <linux/quotaops.h> 11#include <linux/fsnotify.h> 12#include <linux/module.h> 13#include <linux/slab.h> 14#include <linux/tty.h> 15#include <linux/namei.h> 16#include <linux/backing-dev.h> 17#include <linux/capability.h> 18#include <linux/security.h> 19#include <linux/mount.h> 20#include <linux/vfs.h> 21#include <linux/fcntl.h> 22#include <asm/uaccess.h> 23#include <linux/fs.h> 24#include <linux/personality.h> 25#include <linux/pagemap.h> 26#include <linux/syscalls.h> 27#include <linux/rcupdate.h> 28#include <linux/audit.h> 29 30int vfs_statfs(struct dentry *dentry, struct kstatfs *buf) 31{ 32 int retval = -ENODEV; 33 34 if (dentry) { 35 retval = -ENOSYS; 36 if (dentry->d_sb->s_op->statfs) { 37 memset(buf, 0, sizeof(*buf)); 38 retval = security_sb_statfs(dentry); 39 if (retval) 40 return retval; 41 retval = dentry->d_sb->s_op->statfs(dentry, buf); 42 if (retval == 0 && buf->f_frsize == 0) 43 buf->f_frsize = buf->f_bsize; 44 } 45 } 46 return retval; 47} 48 49EXPORT_SYMBOL(vfs_statfs); 50 51static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf) 52{ 53 struct kstatfs st; 54 int retval; 55 56 retval = vfs_statfs(dentry, &st); 57 if (retval) 58 return retval; 59 60 if (sizeof(*buf) == sizeof(st)) 61 memcpy(buf, &st, sizeof(st)); 62 else { 63 if (sizeof buf->f_blocks == 4) { 64 if ((st.f_blocks | st.f_bfree | st.f_bavail) & 65 0xffffffff00000000ULL) 66 return -EOVERFLOW; 67 /* 68 * f_files and f_ffree may be -1; it's okay to stuff 69 * that into 32 bits 70 */ 71 if (st.f_files != -1 && 72 (st.f_files & 0xffffffff00000000ULL)) 73 return -EOVERFLOW; 74 if (st.f_ffree != -1 && 75 (st.f_ffree & 0xffffffff00000000ULL)) 76 return -EOVERFLOW; 77 } 78 79 buf->f_type = st.f_type; 80 buf->f_bsize = st.f_bsize; 81 buf->f_blocks = st.f_blocks; 82 buf->f_bfree = st.f_bfree; 83 buf->f_bavail = st.f_bavail; 84 buf->f_files = st.f_files; 85 buf->f_ffree = st.f_ffree; 86 buf->f_fsid = st.f_fsid; 87 buf->f_namelen = st.f_namelen; 88 buf->f_frsize = st.f_frsize; 89 memset(buf->f_spare, 0, sizeof(buf->f_spare)); 90 } 91 return 0; 92} 93 94static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf) 95{ 96 struct kstatfs st; 97 int retval; 98 99 retval = vfs_statfs(dentry, &st); 100 if (retval) 101 return retval; 102 103 if (sizeof(*buf) == sizeof(st)) 104 memcpy(buf, &st, sizeof(st)); 105 else { 106 buf->f_type = st.f_type; 107 buf->f_bsize = st.f_bsize; 108 buf->f_blocks = st.f_blocks; 109 buf->f_bfree = st.f_bfree; 110 buf->f_bavail = st.f_bavail; 111 buf->f_files = st.f_files; 112 buf->f_ffree = st.f_ffree; 113 buf->f_fsid = st.f_fsid; 114 buf->f_namelen = st.f_namelen; 115 buf->f_frsize = st.f_frsize; 116 memset(buf->f_spare, 0, sizeof(buf->f_spare)); 117 } 118 return 0; 119} 120 121asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf) 122{ 123 struct nameidata nd; 124 int error; 125 126 error = user_path_walk(path, &nd); 127 if (!error) { 128 struct statfs tmp; 129 error = vfs_statfs_native(nd.dentry, &tmp); 130 if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) 131 error = -EFAULT; 132 path_release(&nd); 133 } 134 return error; 135} 136 137 138asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf) 139{ 140 struct nameidata nd; 141 long error; 142 143 if (sz != sizeof(*buf)) 144 return -EINVAL; 145 error = user_path_walk(path, &nd); 146 if (!error) { 147 struct statfs64 tmp; 148 error = vfs_statfs64(nd.dentry, &tmp); 149 if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) 150 error = -EFAULT; 151 path_release(&nd); 152 } 153 return error; 154} 155 156 157asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf) 158{ 159 struct file * file; 160 struct statfs tmp; 161 int error; 162 163 error = -EBADF; 164 file = fget(fd); 165 if (!file) 166 goto out; 167 error = vfs_statfs_native(file->f_path.dentry, &tmp); 168 if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) 169 error = -EFAULT; 170 fput(file); 171out: 172 return error; 173} 174 175asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf) 176{ 177 struct file * file; 178 struct statfs64 tmp; 179 int error; 180 181 if (sz != sizeof(*buf)) 182 return -EINVAL; 183 184 error = -EBADF; 185 file = fget(fd); 186 if (!file) 187 goto out; 188 error = vfs_statfs64(file->f_path.dentry, &tmp); 189 if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) 190 error = -EFAULT; 191 fput(file); 192out: 193 return error; 194} 195 196int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, 197 struct file *filp) 198{ 199 int err; 200 struct iattr newattrs; 201 202 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ 203 if (length < 0) 204 return -EINVAL; 205 206 newattrs.ia_size = length; 207 newattrs.ia_valid = ATTR_SIZE | time_attrs; 208 if (filp) { 209 newattrs.ia_file = filp; 210 newattrs.ia_valid |= ATTR_FILE; 211 } 212 213 /* Remove suid/sgid on truncate too */ 214 newattrs.ia_valid |= should_remove_suid(dentry); 215 216 mutex_lock(&dentry->d_inode->i_mutex); 217 err = notify_change(dentry, &newattrs); 218 mutex_unlock(&dentry->d_inode->i_mutex); 219 return err; 220} 221 222static long do_sys_truncate(const char __user * path, loff_t length) 223{ 224 struct nameidata nd; 225 struct inode * inode; 226 int error; 227 228 error = -EINVAL; 229 if (length < 0) /* sorry, but loff_t says... */ 230 goto out; 231 232 error = user_path_walk(path, &nd); 233 if (error) 234 goto out; 235 inode = nd.dentry->d_inode; 236 237 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ 238 error = -EISDIR; 239 if (S_ISDIR(inode->i_mode)) 240 goto dput_and_out; 241 242 error = -EINVAL; 243 if (!S_ISREG(inode->i_mode)) 244 goto dput_and_out; 245 246 error = vfs_permission(&nd, MAY_WRITE); 247 if (error) 248 goto dput_and_out; 249 250 error = -EROFS; 251 if (IS_RDONLY(inode)) 252 goto dput_and_out; 253 254 error = -EPERM; 255 if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) 256 goto dput_and_out; 257 258 /* 259 * Make sure that there are no leases. 260 */ 261 error = break_lease(inode, FMODE_WRITE); 262 if (error) 263 goto dput_and_out; 264 265 error = get_write_access(inode); 266 if (error) 267 goto dput_and_out; 268 269 error = locks_verify_truncate(inode, NULL, length); 270 if (!error) { 271 DQUOT_INIT(inode); 272 error = do_truncate(nd.dentry, length, 0, NULL); 273 } 274 put_write_access(inode); 275 276dput_and_out: 277 path_release(&nd); 278out: 279 return error; 280} 281 282asmlinkage long sys_truncate(const char __user * path, unsigned long length) 283{ 284 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */ 285 return do_sys_truncate(path, (long)length); 286} 287 288static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) 289{ 290 struct inode * inode; 291 struct dentry *dentry; 292 struct file * file; 293 int error; 294 295 error = -EINVAL; 296 if (length < 0) 297 goto out; 298 error = -EBADF; 299 file = fget(fd); 300 if (!file) 301 goto out; 302 303 /* explicitly opened as large or we are on 64-bit box */ 304 if (file->f_flags & O_LARGEFILE) 305 small = 0; 306 307 dentry = file->f_path.dentry; 308 inode = dentry->d_inode; 309 error = -EINVAL; 310 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) 311 goto out_putf; 312 313 error = -EINVAL; 314 315 /* Foxconn modified start pling 12/04/2009 */ 316 /* Remove large file limitation */ 317#if (!defined SAMBA_ENABLE) 318 /* Cannot ftruncate over 2^31 bytes without large file support */ 319 if (small && length > MAX_NON_LFS) 320 goto out_putf; 321#endif 322 /* Foxconn modified end pling 12/04/2009 */ 323 324 error = -EPERM; 325 if (IS_APPEND(inode)) 326 goto out_putf; 327 328 error = locks_verify_truncate(inode, file, length); 329 if (!error) 330 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file); 331out_putf: 332 fput(file); 333out: 334 return error; 335} 336 337asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) 338{ 339 long ret = do_sys_ftruncate(fd, length, 1); 340 /* avoid REGPARM breakage on x86: */ 341 prevent_tail_call(ret); 342 return ret; 343} 344 345/* LFS versions of truncate are only needed on 32 bit machines */ 346#if BITS_PER_LONG == 32 347asmlinkage long sys_truncate64(const char __user * path, loff_t length) 348{ 349 return do_sys_truncate(path, length); 350} 351 352asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) 353{ 354 long ret = do_sys_ftruncate(fd, length, 0); 355 /* avoid REGPARM breakage on x86: */ 356 prevent_tail_call(ret); 357 return ret; 358} 359#endif 360 361/* 362 * access() needs to use the real uid/gid, not the effective uid/gid. 363 * We do this by temporarily clearing all FS-related capabilities and 364 * switching the fsuid/fsgid around to the real ones. 365 */ 366asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode) 367{ 368 struct nameidata nd; 369 int old_fsuid, old_fsgid; 370 kernel_cap_t old_cap; 371 int res; 372 373 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ 374 return -EINVAL; 375 376 old_fsuid = current->fsuid; 377 old_fsgid = current->fsgid; 378 old_cap = current->cap_effective; 379 380 current->fsuid = current->uid; 381 current->fsgid = current->gid; 382 383 if (current->uid) 384 cap_clear(current->cap_effective); 385 else 386 current->cap_effective = current->cap_permitted; 387 388 res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd); 389 if (res) 390 goto out; 391 392 res = vfs_permission(&nd, mode); 393 /* SuS v2 requires we report a read only fs too */ 394 if(res || !(mode & S_IWOTH) || 395 special_file(nd.dentry->d_inode->i_mode)) 396 goto out_path_release; 397 398 if(IS_RDONLY(nd.dentry->d_inode)) 399 res = -EROFS; 400 401out_path_release: 402 path_release(&nd); 403out: 404 current->fsuid = old_fsuid; 405 current->fsgid = old_fsgid; 406 current->cap_effective = old_cap; 407 408 return res; 409} 410 411asmlinkage long sys_access(const char __user *filename, int mode) 412{ 413 return sys_faccessat(AT_FDCWD, filename, mode); 414} 415 416asmlinkage long sys_chdir(const char __user * filename) 417{ 418 struct nameidata nd; 419 int error; 420 421 error = __user_walk(filename, 422 LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd); 423 if (error) 424 goto out; 425 426 error = vfs_permission(&nd, MAY_EXEC); 427 if (error) 428 goto dput_and_out; 429 430 set_fs_pwd(current->fs, nd.mnt, nd.dentry); 431 432dput_and_out: 433 path_release(&nd); 434out: 435 return error; 436} 437 438asmlinkage long sys_fchdir(unsigned int fd) 439{ 440 struct file *file; 441 struct dentry *dentry; 442 struct inode *inode; 443 struct vfsmount *mnt; 444 int error; 445 446 error = -EBADF; 447 file = fget(fd); 448 if (!file) 449 goto out; 450 451 dentry = file->f_path.dentry; 452 mnt = file->f_path.mnt; 453 inode = dentry->d_inode; 454 455 error = -ENOTDIR; 456 if (!S_ISDIR(inode->i_mode)) 457 goto out_putf; 458 459 error = file_permission(file, MAY_EXEC); 460 if (!error) 461 set_fs_pwd(current->fs, mnt, dentry); 462out_putf: 463 fput(file); 464out: 465 return error; 466} 467 468asmlinkage long sys_chroot(const char __user * filename) 469{ 470 struct nameidata nd; 471 int error; 472 473 error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd); 474 if (error) 475 goto out; 476 477 error = vfs_permission(&nd, MAY_EXEC); 478 if (error) 479 goto dput_and_out; 480 481 error = -EPERM; 482 if (!capable(CAP_SYS_CHROOT)) 483 goto dput_and_out; 484 485 set_fs_root(current->fs, nd.mnt, nd.dentry); 486 set_fs_altroot(); 487 error = 0; 488dput_and_out: 489 path_release(&nd); 490out: 491 return error; 492} 493 494asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) 495{ 496 struct inode * inode; 497 struct dentry * dentry; 498 struct file * file; 499 int err = -EBADF; 500 struct iattr newattrs; 501 502 file = fget(fd); 503 if (!file) 504 goto out; 505 506 dentry = file->f_path.dentry; 507 inode = dentry->d_inode; 508 509 audit_inode(NULL, inode); 510 511 err = -EROFS; 512 if (IS_RDONLY(inode)) 513 goto out_putf; 514 err = -EPERM; 515 if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) 516 goto out_putf; 517 mutex_lock(&inode->i_mutex); 518 if (mode == (mode_t) -1) 519 mode = inode->i_mode; 520 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); 521 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; 522 err = notify_change(dentry, &newattrs); 523 mutex_unlock(&inode->i_mutex); 524 525out_putf: 526 fput(file); 527out: 528 return err; 529} 530 531asmlinkage long sys_fchmodat(int dfd, const char __user *filename, 532 mode_t mode) 533{ 534 struct nameidata nd; 535 struct inode * inode; 536 int error; 537 struct iattr newattrs; 538 539 error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd); 540 if (error) 541 goto out; 542 inode = nd.dentry->d_inode; 543 544 error = -EROFS; 545 if (IS_RDONLY(inode)) 546 goto dput_and_out; 547 548 error = -EPERM; 549 if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) 550 goto dput_and_out; 551 552 mutex_lock(&inode->i_mutex); 553 if (mode == (mode_t) -1) 554 mode = inode->i_mode; 555 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); 556 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; 557 error = notify_change(nd.dentry, &newattrs); 558 mutex_unlock(&inode->i_mutex); 559 560dput_and_out: 561 path_release(&nd); 562out: 563 return error; 564} 565 566asmlinkage long sys_chmod(const char __user *filename, mode_t mode) 567{ 568 return sys_fchmodat(AT_FDCWD, filename, mode); 569} 570 571static int chown_common(struct dentry * dentry, uid_t user, gid_t group) 572{ 573 struct inode * inode; 574 int error; 575 struct iattr newattrs; 576 577 error = -ENOENT; 578 if (!(inode = dentry->d_inode)) { 579 printk(KERN_ERR "chown_common: NULL inode\n"); 580 goto out; 581 } 582 error = -EROFS; 583 if (IS_RDONLY(inode)) 584 goto out; 585 error = -EPERM; 586 if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) 587 goto out; 588 newattrs.ia_valid = ATTR_CTIME; 589 if (user != (uid_t) -1) { 590 newattrs.ia_valid |= ATTR_UID; 591 newattrs.ia_uid = user; 592 } 593 if (group != (gid_t) -1) { 594 newattrs.ia_valid |= ATTR_GID; 595 newattrs.ia_gid = group; 596 } 597 if (!S_ISDIR(inode->i_mode)) 598 newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID; 599 mutex_lock(&inode->i_mutex); 600 error = notify_change(dentry, &newattrs); 601 mutex_unlock(&inode->i_mutex); 602out: 603 return error; 604} 605 606asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) 607{ 608 struct nameidata nd; 609 int error; 610 611 error = user_path_walk(filename, &nd); 612 if (error) 613 goto out; 614 error = chown_common(nd.dentry, user, group); 615 path_release(&nd); 616out: 617 return error; 618} 619 620asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user, 621 gid_t group, int flag) 622{ 623 struct nameidata nd; 624 int error = -EINVAL; 625 int follow; 626 627 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 628 goto out; 629 630 follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; 631 error = __user_walk_fd(dfd, filename, follow, &nd); 632 if (error) 633 goto out; 634 error = chown_common(nd.dentry, user, group); 635 path_release(&nd); 636out: 637 return error; 638} 639 640asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group) 641{ 642 struct nameidata nd; 643 int error; 644 645 error = user_path_walk_link(filename, &nd); 646 if (error) 647 goto out; 648 error = chown_common(nd.dentry, user, group); 649 path_release(&nd); 650out: 651 return error; 652} 653 654 655asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) 656{ 657 struct file * file; 658 int error = -EBADF; 659 struct dentry * dentry; 660 661 file = fget(fd); 662 if (!file) 663 goto out; 664 665 dentry = file->f_path.dentry; 666 audit_inode(NULL, dentry->d_inode); 667 error = chown_common(dentry, user, group); 668 fput(file); 669out: 670 return error; 671} 672 673static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, 674 int flags, struct file *f, 675 int (*open)(struct inode *, struct file *)) 676{ 677 struct inode *inode; 678 int error; 679 680 f->f_flags = flags; 681 f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | 682 FMODE_PREAD | FMODE_PWRITE; 683 inode = dentry->d_inode; 684 if (f->f_mode & FMODE_WRITE) { 685 error = get_write_access(inode); 686 if (error) 687 goto cleanup_file; 688 } 689 690 f->f_mapping = inode->i_mapping; 691 f->f_path.dentry = dentry; 692 f->f_path.mnt = mnt; 693 f->f_pos = 0; 694 f->f_op = fops_get(inode->i_fop); 695 file_move(f, &inode->i_sb->s_files); 696 697 if (!open && f->f_op) 698 open = f->f_op->open; 699 if (open) { 700 error = open(inode, f); 701 if (error) 702 goto cleanup_all; 703 } 704 705 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); 706 707 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); 708 709 /* NB: we're sure to have correct a_ops only after f_op->open */ 710 if (f->f_flags & O_DIRECT) { 711 if (!f->f_mapping->a_ops || 712 ((!f->f_mapping->a_ops->direct_IO) && 713 (!f->f_mapping->a_ops->get_xip_page))) { 714 fput(f); 715 f = ERR_PTR(-EINVAL); 716 } 717 } 718 719 return f; 720 721cleanup_all: 722 fops_put(f->f_op); 723 if (f->f_mode & FMODE_WRITE) 724 put_write_access(inode); 725 file_kill(f); 726 f->f_path.dentry = NULL; 727 f->f_path.mnt = NULL; 728cleanup_file: 729 put_filp(f); 730 dput(dentry); 731 mntput(mnt); 732 return ERR_PTR(error); 733} 734 735/* 736 * Note that while the flag value (low two bits) for sys_open means: 737 * 00 - read-only 738 * 01 - write-only 739 * 10 - read-write 740 * 11 - special 741 * it is changed into 742 * 00 - no permissions needed 743 * 01 - read-permission 744 * 10 - write-permission 745 * 11 - read-write 746 * for the internal routines (ie open_namei()/follow_link() etc). 00 is 747 * used by symlinks. 748 */ 749static struct file *do_filp_open(int dfd, const char *filename, int flags, 750 int mode) 751{ 752 int namei_flags, error; 753 struct nameidata nd; 754 755 namei_flags = flags; 756 if ((namei_flags+1) & O_ACCMODE) 757 namei_flags++; 758 759 error = open_namei(dfd, filename, namei_flags, mode, &nd); 760 if (!error) 761 return nameidata_to_filp(&nd, flags); 762 763 return ERR_PTR(error); 764} 765 766struct file *filp_open(const char *filename, int flags, int mode) 767{ 768 return do_filp_open(AT_FDCWD, filename, flags, mode); 769} 770EXPORT_SYMBOL(filp_open); 771 772/** 773 * lookup_instantiate_filp - instantiates the open intent filp 774 * @nd: pointer to nameidata 775 * @dentry: pointer to dentry 776 * @open: open callback 777 * 778 * Helper for filesystems that want to use lookup open intents and pass back 779 * a fully instantiated struct file to the caller. 780 * This function is meant to be called from within a filesystem's 781 * lookup method. 782 * Beware of calling it for non-regular files! Those ->open methods might block 783 * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo, 784 * leading to a deadlock, as nobody can open that fifo anymore, because 785 * another process to open fifo will block on locked parent when doing lookup). 786 * Note that in case of error, nd->intent.open.file is destroyed, but the 787 * path information remains valid. 788 * If the open callback is set to NULL, then the standard f_op->open() 789 * filesystem callback is substituted. 790 */ 791struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry, 792 int (*open)(struct inode *, struct file *)) 793{ 794 if (IS_ERR(nd->intent.open.file)) 795 goto out; 796 if (IS_ERR(dentry)) 797 goto out_err; 798 nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->mnt), 799 nd->intent.open.flags - 1, 800 nd->intent.open.file, 801 open); 802out: 803 return nd->intent.open.file; 804out_err: 805 release_open_intent(nd); 806 nd->intent.open.file = (struct file *)dentry; 807 goto out; 808} 809EXPORT_SYMBOL_GPL(lookup_instantiate_filp); 810 811/** 812 * nameidata_to_filp - convert a nameidata to an open filp. 813 * @nd: pointer to nameidata 814 * @flags: open flags 815 * 816 * Note that this function destroys the original nameidata 817 */ 818struct file *nameidata_to_filp(struct nameidata *nd, int flags) 819{ 820 struct file *filp; 821 822 /* Pick up the filp from the open intent */ 823 filp = nd->intent.open.file; 824 /* Has the filesystem initialised the file for us? */ 825 if (filp->f_path.dentry == NULL) 826 filp = __dentry_open(nd->dentry, nd->mnt, flags, filp, NULL); 827 else 828 path_release(nd); 829 return filp; 830} 831 832/* 833 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an 834 * error. 835 */ 836struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) 837{ 838 int error; 839 struct file *f; 840 841 error = -ENFILE; 842 f = get_empty_filp(); 843 if (f == NULL) { 844 dput(dentry); 845 mntput(mnt); 846 return ERR_PTR(error); 847 } 848 849 return __dentry_open(dentry, mnt, flags, f, NULL); 850} 851EXPORT_SYMBOL(dentry_open); 852 853/* 854 * Find an empty file descriptor entry, and mark it busy. 855 */ 856int get_unused_fd(void) 857{ 858 struct files_struct * files = current->files; 859 int fd, error; 860 struct fdtable *fdt; 861 862 error = -EMFILE; 863 spin_lock(&files->file_lock); 864 865repeat: 866 fdt = files_fdtable(files); 867 fd = find_next_zero_bit(fdt->open_fds->fds_bits, fdt->max_fds, 868 files->next_fd); 869 870 /* 871 * N.B. For clone tasks sharing a files structure, this test 872 * will limit the total number of files that can be opened. 873 */ 874 if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) 875 goto out; 876 877 /* Do we need to expand the fd array or fd set? */ 878 error = expand_files(files, fd); 879 if (error < 0) 880 goto out; 881 882 if (error) { 883 /* 884 * If we needed to expand the fs array we 885 * might have blocked - try again. 886 */ 887 error = -EMFILE; 888 goto repeat; 889 } 890 891 FD_SET(fd, fdt->open_fds); 892 FD_CLR(fd, fdt->close_on_exec); 893 files->next_fd = fd + 1; 894 /* Sanity check */ 895 if (fdt->fd[fd] != NULL) { 896 printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd); 897 fdt->fd[fd] = NULL; 898 } 899 error = fd; 900 901out: 902 spin_unlock(&files->file_lock); 903 return error; 904} 905 906EXPORT_SYMBOL(get_unused_fd); 907 908static void __put_unused_fd(struct files_struct *files, unsigned int fd) 909{ 910 struct fdtable *fdt = files_fdtable(files); 911 __FD_CLR(fd, fdt->open_fds); 912 if (fd < files->next_fd) 913 files->next_fd = fd; 914} 915 916void fastcall put_unused_fd(unsigned int fd) 917{ 918 struct files_struct *files = current->files; 919 spin_lock(&files->file_lock); 920 __put_unused_fd(files, fd); 921 spin_unlock(&files->file_lock); 922} 923 924EXPORT_SYMBOL(put_unused_fd); 925 926/* 927 * Install a file pointer in the fd array. 928 * 929 * The VFS is full of places where we drop the files lock between 930 * setting the open_fds bitmap and installing the file in the file 931 * array. At any such point, we are vulnerable to a dup2() race 932 * installing a file in the array before us. We need to detect this and 933 * fput() the struct file we are about to overwrite in this case. 934 * 935 * It should never happen - if we allow dup2() do it, _really_ bad things 936 * will follow. 937 */ 938 939void fastcall fd_install(unsigned int fd, struct file * file) 940{ 941 struct files_struct *files = current->files; 942 struct fdtable *fdt; 943 spin_lock(&files->file_lock); 944 fdt = files_fdtable(files); 945 BUG_ON(fdt->fd[fd] != NULL); 946 rcu_assign_pointer(fdt->fd[fd], file); 947 spin_unlock(&files->file_lock); 948} 949 950EXPORT_SYMBOL(fd_install); 951 952long do_sys_open(int dfd, const char __user *filename, int flags, int mode) 953{ 954 char *tmp = getname(filename); 955 int fd = PTR_ERR(tmp); 956 957 if (!IS_ERR(tmp)) { 958 fd = get_unused_fd(); 959 if (fd >= 0) { 960 struct file *f = do_filp_open(dfd, tmp, flags, mode); 961 if (IS_ERR(f)) { 962 put_unused_fd(fd); 963 fd = PTR_ERR(f); 964 } else { 965 fsnotify_open(f->f_path.dentry); 966 fd_install(fd, f); 967 } 968 } 969 putname(tmp); 970 } 971 return fd; 972} 973 974asmlinkage long sys_open(const char __user *filename, int flags, int mode) 975{ 976 long ret; 977 978 if (force_o_largefile()) 979 flags |= O_LARGEFILE; 980 981 ret = do_sys_open(AT_FDCWD, filename, flags, mode); 982 /* avoid REGPARM breakage on x86: */ 983 prevent_tail_call(ret); 984 return ret; 985} 986EXPORT_SYMBOL_GPL(sys_open); 987 988asmlinkage long sys_openat(int dfd, const char __user *filename, int flags, 989 int mode) 990{ 991 long ret; 992 993 if (force_o_largefile()) 994 flags |= O_LARGEFILE; 995 996 ret = do_sys_open(dfd, filename, flags, mode); 997 /* avoid REGPARM breakage on x86: */ 998 prevent_tail_call(ret); 999 return ret; 1000} 1001 1002#ifndef __alpha__ 1003 1004/* 1005 * For backward compatibility? Maybe this should be moved 1006 * into arch/i386 instead? 1007 */ 1008asmlinkage long sys_creat(const char __user * pathname, int mode) 1009{ 1010 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); 1011} 1012 1013#endif 1014 1015/* 1016 * "id" is the POSIX thread ID. We use the 1017 * files pointer for this.. 1018 */ 1019int filp_close(struct file *filp, fl_owner_t id) 1020{ 1021 int retval = 0; 1022 1023 if (!file_count(filp)) { 1024 printk(KERN_ERR "VFS: Close: file count is 0\n"); 1025 return 0; 1026 } 1027 1028 if (filp->f_op && filp->f_op->flush) 1029 retval = filp->f_op->flush(filp, id); 1030 1031 dnotify_flush(filp, id); 1032 locks_remove_posix(filp, id); 1033 fput(filp); 1034 return retval; 1035} 1036 1037EXPORT_SYMBOL(filp_close); 1038 1039/* 1040 * Careful here! We test whether the file pointer is NULL before 1041 * releasing the fd. This ensures that one clone task can't release 1042 * an fd while another clone is opening it. 1043 */ 1044asmlinkage long sys_close(unsigned int fd) 1045{ 1046 struct file * filp; 1047 struct files_struct *files = current->files; 1048 struct fdtable *fdt; 1049 int retval; 1050 1051 spin_lock(&files->file_lock); 1052 fdt = files_fdtable(files); 1053 if (fd >= fdt->max_fds) 1054 goto out_unlock; 1055 filp = fdt->fd[fd]; 1056 if (!filp) 1057 goto out_unlock; 1058 rcu_assign_pointer(fdt->fd[fd], NULL); 1059 FD_CLR(fd, fdt->close_on_exec); 1060 __put_unused_fd(files, fd); 1061 spin_unlock(&files->file_lock); 1062 retval = filp_close(filp, files); 1063 1064 /* can't restart close syscall because file table entry was cleared */ 1065 if (unlikely(retval == -ERESTARTSYS || 1066 retval == -ERESTARTNOINTR || 1067 retval == -ERESTARTNOHAND || 1068 retval == -ERESTART_RESTARTBLOCK)) 1069 retval = -EINTR; 1070 1071 return retval; 1072 1073out_unlock: 1074 spin_unlock(&files->file_lock); 1075 return -EBADF; 1076} 1077 1078EXPORT_SYMBOL(sys_close); 1079 1080/* 1081 * This routine simulates a hangup on the tty, to arrange that users 1082 * are given clean terminals at login time. 1083 */ 1084asmlinkage long sys_vhangup(void) 1085{ 1086 if (capable(CAP_SYS_TTY_CONFIG)) { 1087 tty_vhangup(current->signal->tty); 1088 return 0; 1089 } 1090 return -EPERM; 1091} 1092 1093/* 1094 * Called when an inode is about to be open. 1095 * We use this to disallow opening large files on 32bit systems if 1096 * the caller didn't specify O_LARGEFILE. On 64bit systems we force 1097 * on this flag in sys_open. 1098 */ 1099int generic_file_open(struct inode * inode, struct file * filp) 1100{ 1101 /* Foxconn modifed start pling 06/12/2009 */ 1102 /* remove "big file" limitation */ 1103#if (!defined SAMBA_ENABLE) 1104 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) 1105 return -EFBIG; 1106#endif 1107 /* Foxconn modifed end pling 06/12/2009 */ 1108 return 0; 1109} 1110 1111EXPORT_SYMBOL(generic_file_open); 1112 1113/* 1114 * This is used by subsystems that don't want seekable 1115 * file descriptors 1116 */ 1117int nonseekable_open(struct inode *inode, struct file *filp) 1118{ 1119 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); 1120 return 0; 1121} 1122 1123EXPORT_SYMBOL(nonseekable_open); 1124