fs/open.c

   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/utime.h>
  10 #include <linux/file.h>
  11 #include <linux/smp_lock.h>
  12 #include <linux/quotaops.h>
  13 #include <linux/module.h>
  14
  15 #include <asm/uaccess.h>
  16
  17 int vfs_statfs(struct super_block *sb, struct statfs *buf)
  18 {
  19         int retval = -ENODEV;
  20
  21         if (sb) {
  22                 retval = -ENOSYS;
  23                 if (sb->s_op && sb->s_op->statfs) {
  24                         memset(buf, 0, sizeof(struct statfs));
  25                         lock_kernel();
  26                         retval = sb->s_op->statfs(sb, buf);
  27                         unlock_kernel();
  28                 }
  29         }
  30         return retval;
  31 }
  32
  33
  34 asmlinkage long sys_statfs(const char * path, struct statfs * buf)
  35 {
  36         struct nameidata nd;
  37         int error;
  38
  39         error = user_path_walk(path, &nd);
  40         if (!error) {
  41                 struct statfs tmp;
  42                 error = vfs_statfs(nd.dentry->d_inode->i_sb, &tmp);
  43                 if (!error && copy_to_user(buf, &tmp, sizeof(struct statfs)))
  44                         error = -EFAULT;
  45                 path_release(&nd);
  46         }
  47         return error;
  48 }
  49
  50 asmlinkage long sys_fstatfs(unsigned int fd, struct statfs * buf)
  51 {
  52         struct file * file;
  53         struct statfs tmp;
  54         int error;
  55
  56         error = -EBADF;
  57         file = fget(fd);
  58         if (!file)
  59                 goto out;
  60         error = vfs_statfs(file->f_dentry->d_inode->i_sb, &tmp);
  61         if (!error && copy_to_user(buf, &tmp, sizeof(struct statfs)))
  62                 error = -EFAULT;
  63         fput(file);
  64 out:
  65         return error;
  66 }
  67
  68 int do_truncate(struct dentry *dentry, loff_t length)
  69 {
  70         struct inode *inode = dentry->d_inode;
  71         int error;
  72         struct iattr newattrs;
  73
  74         /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
  75         if (length < 0)
  76                 return -EINVAL;
  77
  78         down(&inode->i_sem);
  79         newattrs.ia_size = length;
  80         newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
  81         error = notify_change(dentry, &newattrs);
  82         up(&inode->i_sem);
  83         return error;
  84 }
  85
  86 static inline long do_sys_truncate(const char * path, loff_t length)
  87 {
  88         struct nameidata nd;
  89         struct inode * inode;
  90         int error;
  91
  92         error = -EINVAL;
  93         if (length < 0) /* sorry, but loff_t says... */
  94                 goto out;
  95
  96         error = user_path_walk(path, &nd);
  97         if (error)
  98                 goto out;
  99         inode = nd.dentry->d_inode;
 100
 101         error = -EACCES;
 102         if (S_ISDIR(inode->i_mode))
 103                 goto dput_and_out;
 104
 105         error = permission(inode,MAY_WRITE);
 106         if (error)
 107                 goto dput_and_out;
 108
 109         error = -EROFS;
 110         if (IS_RDONLY(inode))
 111                 goto dput_and_out;
 112
 113         error = -EPERM;
 114         if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 115                 goto dput_and_out;
 116
 117         lock_kernel();
 118         error = get_write_access(inode);
 119         if (error)
 120                 goto dput_and_out;
 121
 122         error = locks_verify_truncate(inode, NULL, length);
 123         if (!error) {
 124                 DQUOT_INIT(inode);
 125                 error = do_truncate(nd.dentry, length);
 126         }
 127         put_write_access(inode);
 128         unlock_kernel();
 129
 130 dput_and_out:
 131         path_release(&nd);
 132 out:
 133         return error;
 134 }
 135
 136 asmlinkage long sys_truncate(const char * path, unsigned long length)
 137 {
 138         return do_sys_truncate(path, length);
 139 }
 140
 141 static inline long do_sys_ftruncate(unsigned int fd, loff_t length)
 142 {
 143         struct inode * inode;
 144         struct dentry *dentry;
 145         struct file * file;
 146         int error;
 147
 148         error = -EINVAL;
 149         if (length < 0)
 150                 goto out;
 151         error = -EBADF;
 152         file = fget(fd);
 153         if (!file)
 154                 goto out;
 155         dentry = file->f_dentry;
 156         inode = dentry->d_inode;
 157         error = -EACCES;
 158         if (S_ISDIR(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
 159                 goto out_putf;
 160         error = -EPERM;
 161         if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 162                 goto out_putf;
 163
 164         lock_kernel();
 165         error = locks_verify_truncate(inode, file, length);
 166         if (!error)
 167                 error = do_truncate(dentry, length);
 168         unlock_kernel();
 169 out_putf:
 170         fput(file);
 171 out:
 172         return error;
 173 }
 174
 175 asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
 176 {
 177         return do_sys_ftruncate(fd, length);
 178 }
 179
 180 /* LFS versions of truncate are only needed on 32 bit machines */
 181 #if BITS_PER_LONG == 32
 182 asmlinkage long sys_truncate64(const char * path, loff_t length)
 183 {
 184         return do_sys_truncate(path, length);
 185 }
 186
 187 asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
 188 {
 189         return do_sys_ftruncate(fd, length);
 190 }
 191 #endif
 192
 193 #if !(defined(__alpha__) || defined(__ia64__))
 194
 195 /*
 196  * sys_utime() can be implemented in user-level using sys_utimes().
 197  * Is this for backwards compatibility?  If so, why not move it
 198  * into the appropriate arch directory (for those architectures that
 199  * need it).
 200  */
 201
 202 /* If times==NULL, set access and modification to current time,
 203  * must be owner or have write permission.
 204  * Else, update from *times, must be owner or super user.
 205  */
 206 asmlinkage long sys_utime(char * filename, struct utimbuf * times)
 207 {
 208         int error;
 209         struct nameidata nd;
 210         struct inode * inode;
 211         struct iattr newattrs;
 212
 213         error = user_path_walk(filename, &nd);
 214         if (error)
 215                 goto out;
 216         inode = nd.dentry->d_inode;
 217
 218         error = -EROFS;
 219         if (IS_RDONLY(inode))
 220                 goto dput_and_out;
 221
 222         /* Don't worry, the checks are done in inode_change_ok() */
 223         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
 224         if (times) {
 225                 error = get_user(newattrs.ia_atime, &times->actime);
 226                 if (!error)
 227                         error = get_user(newattrs.ia_mtime, &times->modtime);
 228                 if (error)
 229                         goto dput_and_out;
 230
 231                 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
 232         } else {
 233                 if (current->fsuid != inode->i_uid &&
 234                     (error = permission(inode,MAY_WRITE)) != 0)
 235                         goto dput_and_out;
 236         }
 237         error = notify_change(nd.dentry, &newattrs);
 238 dput_and_out:
 239         path_release(&nd);
 240 out:
 241         return error;
 242 }
 243
 244 #endif
 245
 246 /* If times==NULL, set access and modification to current time,
 247  * must be owner or have write permission.
 248  * Else, update from *times, must be owner or super user.
 249  */
 250 asmlinkage long sys_utimes(char * filename, struct timeval * utimes)
 251 {
 252         int error;
 253         struct nameidata nd;
 254         struct inode * inode;
 255         struct iattr newattrs;
 256
 257         error = user_path_walk(filename, &nd);
 258
 259         if (error)
 260                 goto out;
 261         inode = nd.dentry->d_inode;
 262
 263         error = -EROFS;
 264         if (IS_RDONLY(inode))
 265                 goto dput_and_out;
 266
 267         /* Don't worry, the checks are done in inode_change_ok() */
 268         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
 269         if (utimes) {
 270                 struct timeval times[2];
 271                 error = -EFAULT;
 272                 if (copy_from_user(&times, utimes, sizeof(times)))
 273                         goto dput_and_out;
 274                 newattrs.ia_atime = times[0].tv_sec;
 275                 newattrs.ia_mtime = times[1].tv_sec;
 276                 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
 277         } else {
 278                 if ((error = permission(inode,MAY_WRITE)) != 0)
 279                         goto dput_and_out;
 280         }
 281         error = notify_change(nd.dentry, &newattrs);
 282 dput_and_out:
 283         path_release(&nd);
 284 out:
 285         return error;
 286 }
 287
 288 /*
 289  * access() needs to use the real uid/gid, not the effective uid/gid.
 290  * We do this by temporarily clearing all FS-related capabilities and
 291  * switching the fsuid/fsgid around to the real ones.
 292  */
 293 asmlinkage long sys_access(const char * filename, int mode)
 294 {
 295         struct nameidata nd;
 296         int old_fsuid, old_fsgid;
 297         kernel_cap_t old_cap;
 298         int res;
 299
 300         if (mode & ~S_IRWXO)    /* where's F_OK, X_OK, W_OK, R_OK? */
 301                 return -EINVAL;
 302
 303         old_fsuid = current->fsuid;
 304         old_fsgid = current->fsgid;
 305         old_cap = current->cap_effective;
 306
 307         current->fsuid = current->uid;
 308         current->fsgid = current->gid;
 309
 310         /* Clear the capabilities if we switch to a non-root user */
 311         if (current->uid)
 312                 cap_clear(current->cap_effective);
 313         else
 314                 current->cap_effective = current->cap_permitted;
 315
 316         res = user_path_walk(filename, &nd);
 317         if (!res) {
 318                 res = permission(nd.dentry->d_inode, mode);
 319                 /* SuS v2 requires we report a read only fs too */
 320                 if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode))
 321                         res = -EROFS;
 322                 path_release(&nd);
 323         }
 324
 325         current->fsuid = old_fsuid;
 326         current->fsgid = old_fsgid;
 327         current->cap_effective = old_cap;
 328
 329         return res;
 330 }
 331
 332 asmlinkage long sys_chdir(const char * filename)
 333 {
 334         int error;
 335         struct nameidata nd;
 336         char *name;
 337
 338         lock_kernel();
 339
 340         name = getname(filename);
 341         error = PTR_ERR(name);
 342         if (IS_ERR(name))
 343                 goto out;
 344
 345         error = 0;
 346         if (path_init(name,LOOKUP_POSITIVE|LOOKUP_FOLLOW|LOOKUP_DIRECTORY,&nd))
 347                 error = path_walk(name, &nd);
 348         putname(name);
 349         if (error)
 350                 goto out;
 351
 352         error = permission(nd.dentry->d_inode,MAY_EXEC);
 353         if (error)
 354                 goto dput_and_out;
 355
 356         set_fs_pwd(current->fs, nd.mnt, nd.dentry);
 357
 358 dput_and_out:
 359         path_release(&nd);
 360 out:
 361         unlock_kernel();
 362         return error;
 363 }
 364
 365 asmlinkage long sys_fchdir(unsigned int fd)
 366 {
 367         struct file *file;
 368         struct dentry *dentry;
 369         struct inode *inode;
 370         struct vfsmount *mnt;
 371         int error;
 372
 373         error = -EBADF;
 374         file = fget(fd);
 375         if (!file)
 376                 goto out;
 377
 378         dentry = file->f_dentry;
 379         mnt = file->f_vfsmnt;
 380         inode = dentry->d_inode;
 381
 382         error = -ENOTDIR;
 383         if (!S_ISDIR(inode->i_mode))
 384                 goto out_putf;
 385
 386         lock_kernel();
 387         error = permission(inode, MAY_EXEC);
 388         if (!error)
 389                 set_fs_pwd(current->fs, mnt, dentry);
 390         unlock_kernel();
 391 out_putf:
 392         fput(file);
 393 out:
 394         return error;
 395 }
 396
 397 asmlinkage long sys_chroot(const char * filename)
 398 {
 399         int error;
 400         struct nameidata nd;
 401         char *name;
 402
 403         lock_kernel();
 404
 405         name = getname(filename);
 406         error = PTR_ERR(name);
 407         if (IS_ERR(name))
 408                 goto out;
 409
 410         path_init(name, LOOKUP_POSITIVE | LOOKUP_FOLLOW |
 411                       LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
 412         error = path_walk(name, &nd);
 413         putname(name);
 414         if (error)
 415                 goto out;
 416
 417         error = permission(nd.dentry->d_inode,MAY_EXEC);
 418         if (error)
 419                 goto dput_and_out;
 420
 421         error = -EPERM;
 422         if (!capable(CAP_SYS_CHROOT))
 423                 goto dput_and_out;
 424
 425         set_fs_root(current->fs, nd.mnt, nd.dentry);
 426         set_fs_altroot();
 427         error = 0;
 428 dput_and_out:
 429         path_release(&nd);
 430 out:
 431         unlock_kernel();
 432         return error;
 433 }
 434
 435 asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
 436 {
 437         struct inode * inode;
 438         struct dentry * dentry;
 439         struct file * file;
 440         int err = -EBADF;
 441         struct iattr newattrs;
 442
 443         file = fget(fd);
 444         if (!file)
 445                 goto out;
 446
 447         dentry = file->f_dentry;
 448         inode = dentry->d_inode;
 449
 450         err = -EROFS;
 451         if (IS_RDONLY(inode))
 452                 goto out_putf;
 453         err = -EPERM;
 454         if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 455                 goto out_putf;
 456         if (mode == (mode_t) -1)
 457                 mode = inode->i_mode;
 458         newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 459         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 460         lock_kernel();
 461         err = notify_change(dentry, &newattrs);
 462         unlock_kernel();
 463
 464 out_putf:
 465         fput(file);
 466 out:
 467         return err;
 468 }
 469
 470 asmlinkage long sys_chmod(const char * filename, mode_t mode)
 471 {
 472         struct nameidata nd;
 473         struct inode * inode;
 474         int error;
 475         struct iattr newattrs;
 476
 477         error = user_path_walk(filename, &nd);
 478         if (error)
 479                 goto out;
 480         inode = nd.dentry->d_inode;
 481
 482         error = -EROFS;
 483         if (IS_RDONLY(inode))
 484                 goto dput_and_out;
 485
 486         error = -EPERM;
 487         if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 488                 goto dput_and_out;
 489
 490         if (mode == (mode_t) -1)
 491                 mode = inode->i_mode;
 492         newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 493         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
 494         error = notify_change(nd.dentry, &newattrs);
 495
 496 dput_and_out:
 497         path_release(&nd);
 498 out:
 499         return error;
 500 }
 501
 502 static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
 503 {
 504         struct inode * inode;
 505         int error;
 506         struct iattr newattrs;
 507
 508         error = -ENOENT;
 509         if (!(inode = dentry->d_inode)) {
 510                 printk("chown_common: NULL inode\n");
 511                 goto out;
 512         }
 513         error = -EROFS;
 514         if (IS_RDONLY(inode))
 515                 goto out;
 516         error = -EPERM;
 517         if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 518                 goto out;
 519         if (user == (uid_t) -1)
 520                 user = inode->i_uid;
 521         if (group == (gid_t) -1)
 522                 group = inode->i_gid;
 523         newattrs.ia_mode = inode->i_mode;
 524         newattrs.ia_uid = user;
 525         newattrs.ia_gid = group;
 526         newattrs.ia_valid =  ATTR_UID | ATTR_GID | ATTR_CTIME;
 527         /*
 528          * If the user or group of a non-directory has been changed by a
 529          * non-root user, remove the setuid bit.
 530          * 19981026     David C Niemi <niemi@tux.org>
 531          *
 532          * Changed this to apply to all users, including root, to avoid
 533          * some races. This is the behavior we had in 2.0. The check for
 534          * non-root was definitely wrong for 2.2 anyway, as it should
 535          * have been using CAP_FSETID rather than fsuid -- 19990830 SD.
 536          */
 537         if ((inode->i_mode & S_ISUID) == S_ISUID &&
 538                 !S_ISDIR(inode->i_mode))
 539         {
 540                 newattrs.ia_mode &= ~S_ISUID;
 541                 newattrs.ia_valid |= ATTR_MODE;
 542         }
 543         /*
 544          * Likewise, if the user or group of a non-directory has been changed
 545          * by a non-root user, remove the setgid bit UNLESS there is no group
 546          * execute bit (this would be a file marked for mandatory locking).
 547          * 19981026     David C Niemi <niemi@tux.org>
 548          *
 549          * Removed the fsuid check (see the comment above) -- 19990830 SD.
 550          */
 551         if (((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
 552                 && !S_ISDIR(inode->i_mode))
 553         {
 554                 newattrs.ia_mode &= ~S_ISGID;
 555                 newattrs.ia_valid |= ATTR_MODE;
 556         }
 557         error = DQUOT_TRANSFER(dentry, &newattrs);
 558 out:
 559         return error;
 560 }
 561
 562 asmlinkage long sys_chown(const char * filename, uid_t user, gid_t group)
 563 {
 564         struct nameidata nd;
 565         int error;
 566
 567         error = user_path_walk(filename, &nd);
 568         if (!error) {
 569                 error = chown_common(nd.dentry, user, group);
 570                 path_release(&nd);
 571         }
 572         return error;
 573 }
 574
 575 asmlinkage long sys_lchown(const char * filename, uid_t user, gid_t group)
 576 {
 577         struct nameidata nd;
 578         int error;
 579
 580         error = user_path_walk_link(filename, &nd);
 581         if (!error) {
 582                 error = chown_common(nd.dentry, user, group);
 583                 path_release(&nd);
 584         }
 585         return error;
 586 }
 587
 588
 589 asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
 590 {
 591         struct file * file;
 592         int error = -EBADF;
 593
 594         file = fget(fd);
 595         if (file) {
 596                 error = chown_common(file->f_dentry, user, group);
 597                 fput(file);
 598         }
 599         return error;
 600 }
 601
 602 /*
 603  * Note that while the flag value (low two bits) for sys_open means:
 604  *      00 - read-only
 605  *      01 - write-only
 606  *      10 - read-write
 607  *      11 - special
 608  * it is changed into
 609  *      00 - no permissions needed
 610  *      01 - read-permission
 611  *      10 - write-permission
 612  *      11 - read-write
 613  * for the internal routines (ie open_namei()/follow_link() etc). 00 is
 614  * used by symlinks.
 615  */
 616 struct file *filp_open(const char * filename, int flags, int mode)
 617 {
 618         int namei_flags, error;
 619         struct nameidata nd;
 620
 621         namei_flags = flags;
 622         if ((namei_flags+1) & O_ACCMODE)
 623                 namei_flags++;
 624         if (namei_flags & O_TRUNC)
 625                 namei_flags |= 2;
 626
 627         error = open_namei(filename, namei_flags, mode, &nd);
 628         if (!error)
 629                 return dentry_open(nd.dentry, nd.mnt, flags);
 630
 631         return ERR_PTR(error);
 632 }
 633
 634 struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
 635 {
 636         struct file * f;
 637         struct inode *inode;
 638         int error;
 639
 640         error = -ENFILE;
 641         f = get_empty_filp();
 642         if (!f)
 643                 goto cleanup_dentry;
 644         f->f_flags = flags;
 645         f->f_mode = (flags+1) & O_ACCMODE;
 646         inode = dentry->d_inode;
 647         if (f->f_mode & FMODE_WRITE) {
 648                 error = get_write_access(inode);
 649                 if (error)
 650                         goto cleanup_file;
 651         }
 652
 653         f->f_dentry = dentry;
 654         f->f_vfsmnt = mnt;
 655         f->f_pos = 0;
 656         f->f_reada = 0;
 657         f->f_op = fops_get(inode->i_fop);
 658         if (inode->i_sb)
 659                 file_move(f, &inode->i_sb->s_files);
 660         if (f->f_op && f->f_op->open) {
 661                 error = f->f_op->open(inode,f);
 662                 if (error)
 663                         goto cleanup_all;
 664         }
 665         f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 666
 667         return f;
 668
 669 cleanup_all:
 670         fops_put(f->f_op);
 671         if (f->f_mode & FMODE_WRITE)
 672                 put_write_access(inode);
 673         f->f_dentry = NULL;
 674         f->f_vfsmnt = NULL;
 675 cleanup_file:
 676         put_filp(f);
 677 cleanup_dentry:
 678         dput(dentry);
 679         mntput(mnt);
 680         return ERR_PTR(error);
 681 }
 682
 683 /*
 684  * Find an empty file descriptor entry, and mark it busy.
 685  */
 686 int get_unused_fd(void)
 687 {
 688         struct files_struct * files = current->files;
 689         int fd, error;
 690
 691         error = -EMFILE;
 692         write_lock(&files->file_lock);
 693
 694 repeat:
 695         fd = find_next_zero_bit(files->open_fds,
 696                                 current->files->max_fdset,
 697                                 files->next_fd);
 698
 699         /*
 700          * N.B. For clone tasks sharing a files structure, this test
 701          * will limit the total number of files that can be opened.
 702          */
 703         if (fd >= current->rlim[RLIMIT_NOFILE].rlim_cur)
 704                 goto out;
 705
 706         /* Do we need to expand the fdset array? */
 707         if (fd >= current->files->max_fdset) {
 708                 error = expand_fdset(files, fd);
 709                 if (!error) {
 710                         error = -EMFILE;
 711                         goto repeat;
 712                 }
 713                 goto out;
 714         }
 715
 716         /*
 717          * Check whether we need to expand the fd array.
 718          */
 719         if (fd >= files->max_fds) {
 720                 error = expand_fd_array(files, fd);
 721                 if (!error) {
 722                         error = -EMFILE;
 723                         goto repeat;
 724                 }
 725                 goto out;
 726         }
 727
 728         FD_SET(fd, files->open_fds);
 729         FD_CLR(fd, files->close_on_exec);
 730         files->next_fd = fd + 1;
 731 #if 1
 732         /* Sanity check */
 733         if (files->fd[fd] != NULL) {
 734                 printk("get_unused_fd: slot %d not NULL!\n", fd);
 735                 files->fd[fd] = NULL;
 736         }
 737 #endif
 738         error = fd;
 739
 740 out:
 741         write_unlock(&files->file_lock);
 742         return error;
 743 }
 744
 745 asmlinkage long sys_open(const char * filename, int flags, int mode)
 746 {
 747         char * tmp;
 748         int fd, error;
 749
 750 #if BITS_PER_LONG != 32
 751         flags |= O_LARGEFILE;
 752 #endif
 753         tmp = getname(filename);
 754         fd = PTR_ERR(tmp);
 755         if (!IS_ERR(tmp)) {
 756                 fd = get_unused_fd();
 757                 if (fd >= 0) {
 758                         struct file * f;
 759                         lock_kernel();
 760                         f = filp_open(tmp, flags, mode);
 761                         unlock_kernel();
 762                         error = PTR_ERR(f);
 763                         if (IS_ERR(f))
 764                                 goto out_error;
 765                         fd_install(fd, f);
 766                 }
 767 out:
 768                 putname(tmp);
 769         }
 770         return fd;
 771
 772 out_error:
 773         put_unused_fd(fd);
 774         fd = error;
 775         goto out;
 776 }
 777
 778 #ifndef __alpha__
 779
 780 /*
 781  * For backward compatibility?  Maybe this should be moved
 782  * into arch/i386 instead?
 783  */
 784 asmlinkage long sys_creat(const char * pathname, int mode)
 785 {
 786         return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
 787 }
 788
 789 #endif
 790
 791 /*
 792  * "id" is the POSIX thread ID. We use the
 793  * files pointer for this..
 794  */
 795 int filp_close(struct file *filp, fl_owner_t id)
 796 {
 797         int retval;
 798
 799         if (!file_count(filp)) {
 800                 printk("VFS: Close: file count is 0\n");
 801                 return 0;
 802         }
 803         retval = 0;
 804         if (filp->f_op && filp->f_op->flush)
 805                 retval = filp->f_op->flush(filp);
 806         locks_remove_posix(filp, id);
 807         fput(filp);
 808         return retval;
 809 }
 810
 811 /*
 812  * Careful here! We test whether the file pointer is NULL before
 813  * releasing the fd. This ensures that one clone task can't release
 814  * an fd while another clone is opening it.
 815  *
 816  * The "release" argument tells us whether or not to mark the fd as free
 817  * or not in the open-files bitmap.  dup2 uses this to retain the fd
 818  * without races.
 819  */
 820 int do_close(unsigned int fd, int release)
 821 {
 822         int error;
 823         struct file * filp;
 824         struct files_struct * files = current->files;
 825
 826         error = -EBADF;
 827         write_lock(&files->file_lock);
 828         filp = frip(files, fd);
 829         if (!filp)
 830                 goto out_unlock;
 831         FD_CLR(fd, files->close_on_exec);
 832         if (release)
 833                 __put_unused_fd(files, fd);
 834         write_unlock(&files->file_lock);
 835         lock_kernel();
 836         error = filp_close(filp, files);
 837         unlock_kernel();
 838 out:
 839         return error;
 840 out_unlock:
 841         write_unlock(&files->file_lock);
 842         goto out;
 843 }
 844
 845 asmlinkage long sys_close(unsigned int fd)
 846 {
 847         return do_close(fd, 1);
 848 }
 849
 850 /*
 851  * This routine simulates a hangup on the tty, to arrange that users
 852  * are given clean terminals at login time.
 853  */
 854 asmlinkage long sys_vhangup(void)
 855 {
 856         if (capable(CAP_SYS_TTY_CONFIG)) {
 857                 tty_vhangup(current->tty);
 858                 return 0;
 859         }
 860         return -EPERM;
 861 }